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- 07/20/16--10:15: _First atmospheric s...
- 07/20/16--16:01: _Drowning in a paper...
- 07/21/16--07:19: _Study reveals Leona...
- 07/21/16--07:17: _Opinion: How we dis...
- 07/22/16--01:17: _How humans and wild...
- 07/22/16--02:48: _Ancient faeces prov...
- 07/14/16--02:40: _Obesity linked to p...
- 07/25/16--12:00: _Changes in brain st...
- 07/26/16--01:33: _Earth, wind and fly...
- 07/26/16--03:26: _Opinion: Can genes ...
- 07/25/16--14:03: _Cambridge pilots si...
- 07/27/16--15:30: _An hour of moderate...
- 07/28/16--02:20: _Carbon dioxide can ...
- 07/28/16--03:10: _Financial cycles of...
- 07/29/16--06:05: _Lines of Thought: F...
- 07/29/16--16:01: _COLOUR: The art and...
- 08/01/16--01:53: _Exhibition reunites...
- 08/01/16--08:00: _FAMIN or feast? New...
- 08/02/16--07:23: _Opinion: How to sav...
- 08/03/16--01:35: _‘Red gene’ in birds...
- 07/14/16--02:40: Obesity linked to premature death, with greatest effect in men
- 07/26/16--01:33: Earth, wind and flyer: the moves of Disco Tony and friends
- 07/26/16--03:26: Opinion: Can genes really predict how well you’ll do academically?
- 07/25/16--14:03: Cambridge pilots simplified visa scheme for Masters' students
- 07/29/16--06:05: Lines of Thought: From Darwin to DNA
- 07/29/16--16:01: COLOUR: The art and science of illuminated manuscripts
Embarking on the first attempt at detecting the atmospheres of planets outside our solar system, a team of Cambridge and international researchers discovered that the exoplanets TRAPPIST-1b and TRAPPIST-1c, approximately 40 light-years away, are unlikely to have puffy, hydrogen-dominated atmospheres such as those usually found on gaseous worlds like Jupiter or Saturn.
The lack of a hydrogen-helium envelope increases the Earth-likeliness of these planets and has caused considerable excitement among researchers taking part in the study. The results of their findings are published today in the journal Nature.
“Humanity’s remote exploration of alien environments has truly started,” said Amaury Triaud, a research fellow at Cambridge’s Institute of Astronomy. “It is tantalizing to think that with another ten similar observations, we would start distinguishing whether those planets are more Venus-like, more Earth-like, or if they are radically different.”
Researchers observed the planets in near-infrared light and used spectroscopy to decode a change of light as the planets transited in front of their stars. During transit, starlight shines through a planet’s atmosphere making it possible to deduce its chemical makeup.
Both planets orbit TRAPPIST-1 – an ultracool dwarf star that is much cooler and redder than the sun, and barely larger than Jupiter. TRAPPIST-1 has a mass 8% that of the Sun and is located in the constellation of Aquarius. The planets orbiting the star were discovered in late 2015 through a series of observations by the TRAnsiting Planets and PlanetesImals Small Telescope (TRAPPIST), a Belgian robotic telescope located at ESO’s (European Southern Observatory’s) La Silla Observatory in Chile. The small size of the star TRAPPIST-1 boosts the signal produced by the planets’ atmospheres, easing their study by nearly 100 times compared to similar planets orbiting stars like the Sun.
TRAPPIST-1b completes a circuit around its red dwarf star in 1.5 days and TRAPPIST-1c in 2.4 days. Thanks to the faintness of the star they orbit, and to the planet’s short orbits, it is possible that parts of their surfaces have temperatures similar to the Earth. While it remains unclear whether the planets are habitable, they are the first worlds for which we can determine the existence of a habitable climate.
On May 4, astronomers took advantage of a rare simultaneous transit, when both planets crossed the face of their star within minutes of each other, to measure starlight as it filtered through any existing atmosphere. This double transit, which occurs only once every two years, provided a chance to hasten the atmospheric study of TRAPPIST-1b and TRAPPIST-1c.
The researchers now hope to use Hubble to conduct follow-up observations to search for thinner atmospheres, composed of elements heavier than hydrogen, like those of Earth and Venus.
Observations from future telescopes, including NASA’s James Webb Space Telescope, will help determine the full composition of these atmospheres and hunt for potential biosignatures, such as carbon dioxide and ozone, in addition to water vapor and methane. Webb also will analyze a planet’s temperature and surface pressure – key factors in assessing its habitability.
“Our observations demonstrate that Hubble has the capacity to play a central role,” said lead researcher Julien de Wit, of the Massachusetts Institute of Technology. “It can carry-out an atmospheric pre-screening, to tell astronomers which of these Earth-sized planets are prime candidates for more detailed study with the Webb telescope.”
The TRAPPIST telescope identified these two Earth-sized worlds during a prototype run for a more ambitious venture, called SPECULOOS, which is currently in construction at Cerro Paranal, Chile. SPECULOOS will monitor 1,000 nearby red dwarf stars seeking additional Earth-sized worlds.
Professor Didier Queloz, Professor of Physics at the Cavendish Laboratory, and a founding member of the project, said: “Within the next five years, SPECULOOS will likely detect 20-30 new Earth-sized planets. All of them will have atmospheres that can be investigated by the James Webb.”
Dr Brice-Olivier Demory, a senior research associate at the Cavendish Laboratory, said: “Soon we will have the right targets, and the right telescopes to start investigating rocky planet atmospheres beyond our Solar system. Finding out whether other worlds are indeed Earth-like is only a matter of time.”
The Hubble Space Telescope is a project of international cooperation between NASA and ESA. Goddard manages the telescope and STScI conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington.
Two Earth-sized exoplanets have become the first rocky worlds to have their atmospheres studied using the Hubble Space Telescope.
One of the world’s largest anti-poverty measures – a scheme designed to guarantee 100 days’ work to poor, rural households in India – has become bogged down in a bureaucratic quagmire, according to recently-published research.
The Mahatma Gandhi National Rural Employment Guarantee Act, 2005 (MNREGA) is the subject of Paper Tiger by Cambridge anthropologist Nayanika Mathur. The Act covers all of India’s rural population (or about 70% of India’s 1.3 billion people) and is supposed to guarantee work for unskilled labourers at the minimum wage.
Launched amid huge fanfare in February 2006, MNREGA’s performance continues to be the object of strenuous debate in India. “MNREGA was put forward as a radical, progressive move, enshrining the right to work,” said Mathur. “This was a sophisticated legislation that potentially has a lot of promise. But I wanted to see first hand how a law authored by elites in New Delhi, in English, gets put into practice in one of the poorest parts of India.”
Mathur chose to study this welfarist statute through an innovative anthropological method: embedding herself within the development bureaucracy of the state in a remote and impoverished Himalayan district.
She spent a total of 18 months following the implementation of MNREGA through different levels of the Indian state. Almost a year was spent living in the town of Gopeshwar in Chamoli district, in the remote central Himalayan state of Uttarakhand. With its high levels of poverty, unemployment and distress out-migration, Mathur chose to base her research in the Himalaya to see how MNREGA was – or wasn’t – being put into practice at a local level.
“The locals thought I was very odd,” said Mathur. “They weren’t suspicious of me, but they couldn’t understand why I was there in the first place. The bureaucrats, in particular, didn’t think anything they do is of worth and feel very neglected and distant from the centre. It took months for the awkwardness to subside and for me to be accepted. But the surprise they felt at having someone take (what they consider) their dull, repetitive bureaucratic work seriously, never quite left them.”
As Mathur followed the MNREGA around the high Himalaya she was surprised to hear it described as an “unimplementable” programme. Despite the desperate need for employment opportunities in rural Himalaya, the welfare scheme was conspicuous by its absence. Paper Tiger, as it meticulously traces the implementation of the MNREGA, presents some surprising findings.
The book argues that MNREGA has largely failed, not because of corruption (as is commonly assumed), but because of its anti-corruption measures. In her role as a participant-observer in small, crumbling government offices in Himalayan India, Mathur found that the legal requirement for transparent functioning had led to an exponential increase in the paperwork demanded of the state bureaucracy. Along with its sheer laboriousness and complexity, this paperwork was intervening in the traditional system of operation of welfare leading to a complete paralysis in welfare.
The extreme reliance on paper, documents, and files in the Indian bureaucracy has a complicated history in India and can be traced back to the operations of the British colonial state in India. Mathur argues that the seemingly-new drive to hold the contemporary Indian state accountable to its citizenry is, in fact, aggravating the documentary foundations of its bureaucracy.
“Ironically, it is the requirements to render the Indian state transparent and accountable that introduced a crisis of implementation with MNREGA,” notes Mathur.
The drive for transparency at a national level also produced problems specific to the region where Mathur conducted her research. In order to stem corruption, a directive was issued asking for all wages to be paid through bank accounts. This created huge problems in the Himalayas where there are very few bank branches, and those that do exist were located miles away from most villages.
Most problematically, women were at risk of losing control over their own wages as they became dependent either on middlemen or male relatives to operate bank accounts for them. Unwittingly, the push for financial transparency had ended up creating an anti-women system.
Despite its evident problems, Mathur believes the Act is a clever, canny piece of legislation. In Paper Tiger, she uses the crisis in the implementation of MNREGA as a case study that helps make broader arguments about the nature of the state – and what it means when welfare schemes are found not to be working as they should.
Added Mathur: “My study of the operations of the state in the Indian Himalaya, allows for an understanding of the failure of the developmental Indian state that is not predicated upon corruption, violence, incapacity, sloth, or simple dysfunction.”
“Rather, my attempt here is to make us understand what the welfare state in practice is. For it is only when we really get our heads round the very nature of the beast can we hope to ever reform it.”
India’s sophisticated laws and progressive policies fail with startling regularity. A new study locates a possible reason as to why in the convoluted bureaucratic system of the Indian state and its obsession with paper
Scribbled notes and sketches on a page in a notebook by Leonardo da Vinci, previously dismissed as irrelevant by an art historian, have been identified as the place where he first recorded his understanding of the laws of friction.
The research by Professor Ian Hutchings, Professor of Manufacturing Engineering at the University of Cambridge and a Fellow of St John’s College, is the first detailed chronological study of Leonardo’s work on friction, and has also shown how he continued to apply his knowledge of the subject to wider work on machines over the next two decades.
It is widely known that Leonardo conducted the first systematic study of friction, which underpins the modern science of “tribology”, but exactly when and how he developed these ideas has been uncertain until now.
Professor Hutchings has discovered that Leonardo’s first statement of the laws of friction is in a tiny notebook measuring just 92 mm x 63 mm. The book, which dates from 1493 and is now held in the Victoria and Albert Museum in London, contains a statement scribbled quickly in Leonardo’s characteristic “mirror writing” from right to left.
Ironically the page had already attracted interest because it also carries a sketch of an old woman in black pencil with a line below reading “cosa bella mortal passa e non dura”, which can be translated as “mortal beauty passes and does not last”. Amid debate surrounding the significance of the quote and speculation that the sketch could represent an aged Helen of Troy, the Director of the V & A in the 1920s referred to the jottings below as “irrelevant notes and diagrams in red chalk”.
Professor Hutchings’s study has, however, revealed that the script and diagrams in red are of great interest to the history of tribology, marking a pivotal moment in Leonardo’s work on the subject.
The rough geometrical figures underneath Leonardo’s red notes show rows of blocks being pulled by a weight hanging over a pulley – in exactly the same kind of experiment students might do today to demonstrate the laws of friction.
Professor Hutchings said: “The sketches and text show Leonardo understood the fundamentals of friction in 1493. He knew that the force of friction acting between two sliding surfaces is proportional to the load pressing the surfaces together and that friction is independent of the apparent area of contact between the two surfaces. These are the ‘laws of friction’ that we nowadays usually credit to a French scientist, Guillaume Amontons, working two hundred years later.”
“Leonardo’s 20-year study of friction, which incorporated his empirical understanding into models for several mechanical systems, confirms his position as a remarkable and inspirational pioneer of tribology.”
Professor Hutchings’s research traces a clear path of development in Leonardo’s studies of friction and demonstrates that he realised that friction, while sometimes useful and even essential, also played a key role in limiting the efficiency of machines.
Sketches of machine elements and mechanisms are pervasive in Leonardo’s notebooks and he used his remarkably sophisticated understanding of friction to analyse the behaviour of wheels and axles, screw threads and pulleys, all important components of the complicated machines he sketched.
He wanted to understand the rules that governed the operation of these machines and knew that friction was important in limiting their efficiency and precision, grasping, for example, that resistance to the rotation of a wheel arose from friction at the axle bearing and calculating its effect.
“Leonardo’s sketches and notes were undoubtedly based on experiments, probably with lubricated contacts,” added Hutchings. “He appreciated that friction depends on the nature of surfaces and the state of lubrication and his use and understanding of the ratios between frictional force and weight was much more nuanced than many have suggested.”
Although he undoubtedly discovered the laws of friction, Leonardo’s work had no influence on the development of the subject over the following centuries and it was certainly unknown to Amontons.
“Leonardo da Vinci’s studies of friction” by Professor Ian Hutchings is published in the journal Wear. The paper can be accessed in full via: http://www.sciencedirect.com/science/article/pii/S0043164816300588
A general article on tribology that discusses its importance in modern engineering can be found at:
A new detailed study of notes and sketches by Leonardo da Vinci has identified a page of scribbles in a tiny notebook as the place where Leonardo first recorded the laws of friction. The research also shows that he went on to apply this knowledge repeatedly to mechanical problems for more than 20 years.
Once travelled by famous historical figures such as Marco Polo and Genghis Khan, the Silk Road was a hugely important network of transport routes connecting eastern China with Central Asia, the Middle East and Europe. It came to prominence during the Chinese Han Dynasty (202 BC to AD 220) and remained a key transport route for the following 2,000 years.
Given that the Silk Road was a melting pot of people, it is no wonder that researchers have suggested that it might have been responsible for the spread of diseases such as bubonic plague, anthrax and leprosy between China and Europe. However, no one one has yet found any evidence to show how diseases in eastern China reached Europe. Travellers might have spread these diseases taking a southerly route via India and the Middle East, or a northerly route via Mongolia and Russia.
But our team, including researchers at the University of Cambridge and China’s Academy of Social Sciences and Gansu Institute for Cultural Relics and Archaeology, has now found the earliest evidence for the spread of infectious disease organisms along the Silk Road. The results have been published in the Journal of Archaeological Science Reports.
We investigated latrines at the Xuanquanzhi relay station, a fortified stopping point along the Silk Road that was built in 111 BC and used until 109 AD. It is located at Dunhuang, at the eastern end of the Tamrin Basin, an arid region that contacts the fearsome Taklamakan Desert. When the latrines were excavated, the archaeologists found sticks with cloth wrapped around one end (see lead image). These have been described in ancient Chinese texts of the period as a personal hygiene tool for wiping the anus after going to the toilet. Some of the cloth had a dark solid material still adhered to it after all this time.
Faeces under the microscope
We realised that this material was faeces when we looked at it with a high-powered optical microscope. We also found the eggs of four species of parasitic intestinal worms in it. This may seem surprising but the eggs of many species of intestinal worms are very tough and may survive thousands of years in the ground. This indicates that some of the people using this latrine 2,000 years ago were infected with parasites. The species included roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura), Taenia sp. tapeworm (likely T. solium, T. asiatica or T. solium) and Chinese liver fluke (Clonorchis sinensis).
Roundworm and whipworm are parasites found right across the world in the past and indicate poor personal hygiene, as the worms are spread by the contamination of food and hands by human faeces. Taenia sp. tapeworm is spread by eating raw or undercooked meat such as pork and beef, and again has been found across large areas of the world in the past.
Meanwhile, Chinese liver fluke – which can cause abdominal pain, diarrhoea, jaundice and liver cancer – is only found in regions of eastern and southern China and Korea, as it has a complex life cycle. It is restricted to areas with wet marshy countryside, as the parasite must pass through the intermediate hosts of a water snail and freshwater fish before it can infect humans. The humans have to eat the fish raw if it is to infect them. In modern times, the closest area to Dunhuang where Chinese liver fluke is found is 1,500km away, and the region where most cases of infection are found is 2,000km away.
Discovering evidence for Chinese liver fluke at a latrine in the arid region of Dunhuang was really exciting. The parasite could not possibly be endemic in that region as there are no marshy areas needed for its life cycle. Instead, it shows that a person who became infected with the liver fluke in eastern or southern China was able to travel the huge distance to this relay station along the Silk Road – at least 1,500km.
Our finding suggests that we now know for sure that the Silk Road was responsible for spreading infectious diseases in ancient times. This makes more likely previous proposals that bubonic plague, leprosy and anthrax could also have been spread along it.
The opinions expressed in this article are those of the individual author(s) and do not represent the views of the University of Cambridge.
Piers Mitchell (Department of Biological Anthropology) discusses what we can learn from rummaging around in 2,000-year-old toilets.
Humans have trained a range of species to help them find food: examples are dogs, falcons and cormorants. These animals are domesticated or taught to cooperate by their owners. Human-animal collaboration in the wild is much rarer. But it has long been known that, in many parts of Africa, people and a species of wax-eating bird called the greater honeyguide work together to find wild bees’ nests which provide a valuable resource to them both.
Honeyguides give a special call to attract people’s attention, then fly from tree to tree to indicate the direction of a bees’ nest. We humans are useful collaborators to honeyguides because of our ability to subdue stinging bees with smoke and chop open their nest, providing wax for the honeyguide and honey for ourselves.
Experiments carried out in the Mozambican bush now show that this unique human-animal relationship has an extra dimension: not only do honeyguides use calls to solicit human partners, but humans use specialised calls to recruit birds’ assistance. Research in the Niassa National Reserve reveals that by using specialised calls to communicate and cooperate with each other, people and wild birds can significantly increase their chances of locating vital sources of calorie-laden food.
In a paper (Reciprocal signaling in honeyguide-human mutualism) published in Science today (22 July 2016), evolutionary biologist Dr Claire Spottiswoode (University of Cambridge and University of Cape Town) and co-authors (conservationists Keith Begg and Dr Colleen Begg of the Niassa Carnivore Project) reveal that honeyguides are able to respond adaptively to specialised signals given by people seeking their collaboration, resulting in two-way communication between humans and wild birds.
This reciprocal relationship plays out in the wild and occurs without any conventional kind of ‘training’ or coercion. “What’s remarkable about the honeyguide-human relationship is that it involves free-living wild animals whose interactions with humans have probably evolved through natural selection, probably over the course of hundreds of thousands of years,” says Spottiswoode, a specialist in bird behavioural ecology in Africa.
“Thanks to the work in Kenya of Hussein Isack, who electrified me as an 11-year-old when I heard him speak in Cape Town, we’ve long known that people can increase their rate of finding bees’ nests by collaborating with honeyguides, sometimes following them for over a kilometre. Keith and Colleen Begg, who do wonderful conservation work in northern Mozambique, alerted me to the Yao people’s traditional practice of using a distinctive call which they believe helps them to recruit honeyguides. This was instantly intriguing – could these calls really be a mode of communication between humans and a wild animal?”
With the help of honey-hunters from the local Yao community, Spottiswoode carried out controlled experiments in Mozambique’s Niassa National Reserve to test whether the birds were able to distinguish the call from other human sounds, and so to respond to it appropriately. The ‘honey-hunting call’ made by honey-hunters, and passed from generation to generation, is a loud trill followed by a short grunt: ‘brrr-hm’.
To discover whether honeyguides associate ‘brrr-hm’ with a specific meaning , Spottiswoode made recordings of this call and two kinds of ‘control’ sounds : arbitrary words called out by the honey-hunters and the calls of another bird species. When these sounds were played back in the wild during experimental honey-hunting trips, birds were much more likely respond to the ‘brrr-hm’ call made to attract them than they were to either of the other sounds.
“The traditional ‘brrr-hm’ call increased the probability of being guided by a honeyguide from 33% to 66%, and the overall probability of being shown a bees’ nest from 16% to 54% compared to the control sounds. In other words, the ‘brrr-hm’ call more than tripled the chances of a successful interaction, yielding honey for the humans and wax for the bird,” says Spottiswoode.
“Intriguingly, people in other parts of Africa use very different sounds for the same purpose – for example, our colleague Brian Wood’s work has shown that Hadza honey-hunters in Tanzania make a melodious whistling sound to recruit honeyguides. We’d love to know whether honeyguides have learnt this language-like variation in human signals across Africa, allowing them to recognise good collaborators among the local people living alongside them.”
The greater honeyguide is widely found in sub-Saharan Africa, where its unassuming brown plumage belies its complex interactions with other species. Its interactions with humans to obtain food are mutually beneficial, but to obtain care for its young it is a brutal exploiter of other birds.
“Like a cuckoo, it lays its eggs in the nests of other birds, and its chick hatches equipped with sharp hooks at the tips of its beak. Only a few days old, the young honeyguide uses these built-in weapons to kill its foster siblings as soon as they hatch,” says Spottiswoode. “So the greater honeyguide is a master of deception and exploitation as well as cooperation – a proper Jekyll and Hyde of the bird world.”
Human cooperation is crucial to honeyguides because bees’ nests are often hidden in inaccessible crevices high up in trees – and honeybees sting ferociously. Therefore the honeyguide waits while an expert human undertakes the dangerous tasks of subduing the bees (by smoking them out using a flaming bundle of twigs and leaves hoisted high into the tree) and extracting the honey from within, usually by felling the entire tree. There is no competition for the prize: the honey-hunters harvest the honey and honeyguides devour the wax combs left behind.
Co-author Dr Colleen Begg adds: “The Niassa National Reserve is as much about people as it is about wildlife, and this is really exemplified by these human-honeyguide interactions that have been forged over thousands of years of coexistence. While many people consider wilderness not to have people in it, at Niassa people are an essential part of the landscape.”
This foraging partnership was recorded in print as early as 1588, when a Portuguese missionary in what is now Mozambique observed a small brown bird slipping into his church to nibble his wax candles. He described how this bird had another remarkable habit: it led men to bees’ nests by calling and flying from tree to tree. Once the nest was located, he wrote in his account of life on the eastern African coast in the 17th century, Ethiopia Oriental, the men harvested the honey and the bird fed on the wax.
“What João dos Santos described was what we now call a mutualism between species. Mutualisms are crucial everywhere in nature, but to our knowledge, the only comparable foraging partnership between wild animals and our own species involves free-living dolphins who chase schools of mullet into fishermen’s nets and in so doing manage to catch more for themselves. It would be fascinating to know whether dolphins respond to special calls made by fishermen, as Pliny the Elder asserted nearly two thousand years ago,” says Spottiswoode.
“Back in Africa, we’re fascinated by the evolution of the honeyguide-human mutualism and, as a next step, we want to test whether young honeyguides learn to recognise local human signals, creating a mosaic of honeyguide cultural variation that reflects that of their human partners. Sadly, the mutualism has already vanished from many parts of Africa. The world is a richer place for wildernesses like Niassa where this astonishing example of human-animal cooperation still thrives.”
The project was funded by the Biotechnology and Biological Sciences Research Council (BBSRC) in the UK and the DST-NRF Centre of Excellence at the FitzPatrick Institute in South Africa.
Inset images: Yao honey-hunter Orlando Yassene harvests honeycombs from a wild bees’ nest in the Niassa National Reserve, Mozambique (Claire Spottiswoode); Yao honey-hunter Orlando Yassene holds a female greater honeyguide temporarily captured for research in the Niassa National Reserve, Mozambique (Claire Spottiswoode); Yao honey-hunter Orlando Yassene chops open a bees’ nest in a felled tree in the Niassa National Reserve, Mozambique (Claire Spottiswoode); Yao honey-hunter Orlando Yassene holds a wax comb (honeyguide food) from a wild bees’ nest harvested in the Niassa National Reserve, Mozambique (Claire Spottiswoode); Claire Spottiswoode interviewing honey-hunter Issufo "Kambunga" Jaime (Romina Gaona).
By following honeyguides, a species of bird, people in Africa are able to locate bees’ nests to harvest honey. Research now reveals that humans use special calls to solicit the help of honeyguides and that honeyguides actively recruit appropriate human partners. This relationship is a rare example of cooperation between humans and free-living animals.
An ancient latrine near a desert in north-western China has revealed the first archaeological evidence that travellers along the Silk Road were responsible for the spread of infectious diseases along huge distances of the route 2,000 years ago.
Cambridge researchers Hui-Yuan Yeh and Piers Mitchell used microscopy to study preserved faeces on ancient ‘personal hygiene sticks’ (used for wiping away faeces from the anus) in the latrine at what was a large Silk Road relay station on the eastern margins of the Tamrin Basin, a region that contains the Taklamakan desert. The latrine is thought to date from 111 BC (Han Dynasty) and was in use until 109 AD.
They found that eggs from four species of parasitic worm (helminths) were present: roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura), tapeworm (Taenia sp.), and Chinese liver fluke (Clonorchis sinensis).
Chinese liver fluke is a parasitic flatworm that causes abdominal pain, diarrhoea, jaundice and liver cancer. It requires well-watered, marshy areas to complete its life cycle. Xuanquanzhi relay station was located at the eastern end of the arid Tamrin Basin, an area that contains the fearsome Taklamakan Desert. The liver fluke could not have been endemic in this dry region.
In fact, based on the current prevalence of the Chinese liver fluke, its closest endemic area to the latrine’s location in Dunhuang is around 1,500km away, and the species is most common in Guandong Province – some 2,000km from Dunhuang.
Researchers from the University of Cambridge’s Department of Archaeology and Anthropology, who conducted the study, suggest that the traveller infected with this liver fluke must have journeyed an enormous distance, and suggest the discovery provides the first reliable evidence for long distance travel with an infectious disease along the Silk Road.
The findings are published today in the Journal of Archaeological Science: Reports.
“When I first saw the Chinese liver fluke egg down the microscope I knew that we had made a momentous discovery,” said Hui-Yuan Yeh, one of the study’s authors. “Our study is the first to use archaeological evidence from a site on the Silk Road to demonstrate that travellers were taking infectious diseases with them over these huge distances.”
The Silk Road (or Silk Route) came to prominence during the Han Dynasty in China (202 BC – AD 220) as merchants, explorers, soldiers and government officials journeyed between East Asia and the Middle East/Mediterranean region.
Researchers have previously suggested that diseases such as bubonic plague, anthrax and leprosy might have been carried by ancient travellers along the legendary trading route, as similar strains have been found in China and Europe.
“Until now there has been no proof that the Silk Road was responsible for the spread of infectious diseases. They could instead have spread between China and Europe via India to the south, or via Mongolia and Russia to the north,” says study lead Piers Mitchell.
The Cambridge team worked alongside Chinese researchers Ruilin Mao and Hui Wang from the Gansu Institute for Cultural Relics and Archaeology, who originally excavated the ancient latrine and relay station in Ganzu Province.
The stop was a popular one on the Silk Road with travellers staying there and government officials using the facility to change their horses and deliver letters. While excavating the latrine, the Chinese team found the personal hygiene sticks with cloth wrapped round one end.
Added Mitchell: “Finding evidence for this species in the latrine indicates that a traveller had come here from a region of China with plenty of water, where the parasite was endemic. This proves for the first time that travellers along the Silk Road really were responsible for the spread of infectious disease along this route in the past.”
Inset: Egg of Chinese liver fluke discovered in the latrine at Xuanquanzhi, viewed using microscopy.
Intestinal parasites as well as goods were carried by travellers on iconic route, say researchers examining ancient latrine.
The World Health Organization estimates that 1.3 billion adults worldwide are overweight, and that a further 600 million are obese. The prevalence of adult obesity is 20% in Europe and 31% in North America.
“On average, overweight people lose about one year of life expectancy, and moderately obese people lose about three years of life expectancy,” says Dr Emanuele Di Angelantonio from the University of Cambridge, the lead author. “We also found that men who were obese were at much higher risk of premature death than obese women. This is consistent with previous observations that obese men have greater insulin resistance, liver fat levels, and diabetes risk than women.”
The study found an increased risk of premature death for people who were underweight, as well as for people classed as overweight. The risk increased steadily and steeply as BMI increased. A similar trend was seen in many parts of the world and for all four main causes of death.
Where the risk of death before age 70 would be 19% and 11% for men and women with a normal BMI, the study found that it would be 29.5% and 14.6% for moderately obese men and women. The authors defined premature deaths as those at ages 35-69 years.
The new study brings together information on the causes of any deaths in 3.9 million adults from 189 previous studies in Europe, North America and elsewhere. At entry to the study all were aged between 20 and 90 years old, and were non-smokers who were not known to have any chronic disease when their BMI was recorded. The analysis is of those who then survived at least another five years.
The authors say that assuming that the associations between high BMI and mortality are largely causal, if those who were overweight or obese had WHO-defined normal levels of BMI, then one in 7 premature deaths in Europe and one in 5 in North America would be avoided.
The Global BMI Mortality Collaboration. Body-mass index and all-cause mortality: individual-participant-data meta-analysis of 239 prospective studies in four continents. Lancet; 13 July 2016; DOI: 10.1016/S0140-6736(16)30175-1
Adapted from a press release from The Lancet
A study of 3.9 million adults published today in The Lancet has found that being overweight or obese is associated with an increased risk of premature death. The risks of coronary heart disease, stroke, respiratory disease and cancer are all increased. Overall, the excess risk of premature death (before age 70) among those who are overweight or obese is about three times as great in men as in women.
In a study published today in the Proceedings of the National Academy of Sciences, researchers from the University of Cambridge and University College London (UCL) used magnetic resonance imaging (MRI) to study the brain structure of almost 300 individuals aged 14-24 years old.
By comparing the brain structure of teenagers of different ages, they found that during this important period of development, the outer regions of the brain, known as the cortex, shrink in size, becoming thinner. However, as this happens, levels of myelin – the sheath that ‘insulates’ nerve fibres, allowing them to communicate efficiently – increase within the cortex.
Previously, myelin was thought mainly to reside in the so-called ‘white matter’, the brain tissue that connects areas of the brain and allows for information to be communicated between brain regions. However, in this new study, the researchers show that it can also be found within the cortex, the ‘grey matter’ of the brain, and that levels increase during teenage years. In particular, the myelin increase occurs in the ‘association cortical areas’, regions of the brain that act as hubs, the major connection points between different regions of the brain network.
Dr Kirstie Whitaker from the Department of Psychiatry at the University of Cambridge, the study’s first author, says: “During our teenage years, our brains continue to develop. When we’re still children, these changes may be more dramatic, but in adolescence we see that the changes refine the detail. The hubs that connect different regions are becoming set in place as the most important connections strengthen. We believe this is where we are seeing myelin increasing in adolescence.”
The researchers compared these MRI measures to the Allen Brain Atlas, which maps regions of the brain by gene expression – the genes that are ‘switched on’ in particular regions. They found that those brain regions that exhibited the greatest MRI changes during the teenage years were those in which genes linked to schizophrenia risk were most strongly expressed.
“Adolescence can be a difficult transitional period and it’s when we typically see the first signs of mental health disorders such as schizophrenia and depression,” explains Professor Ed Bullmore, Head of Psychiatry at Cambridge. “This study gives us a clue why this is the case: it’s during these teenage years that those brain regions that have the strongest link to the schizophrenia risk genes are developing most rapidly.
“As these regions are important hubs that control how regions of our brain communicate with each other, it shouldn’t be too surprising that when something goes wrong there, it will affect how smoothly our brains work. If one imagines these major hubs of the brain network to be like international airports in the airline network, then we can see that disrupting the development of brain hubs could have as big an impact on communication of information across the brain network as disruption of a major airport, like Heathrow, will have on flow of passenger traffic across the airline network.”
The researchers are confident about the robustness of their findings as they divided their participants into a ‘discovery cohort’ of 100 young people and a ‘validation cohort’ of almost 200 young people to ensure the results could be replicated.
The study was funded by a Strategic Award from the Wellcome Trust to the Neuroscience in Psychiatry Network (NSPN) Consortium.
Dr Raliza Stoyanova in the Neuroscience and Mental Health team at Wellcome, which funded the study, comments: “A number of mental health conditions first manifest during adolescence. Although we know that the adolescent brain undergoes dramatic structural changes, the precise nature of those changes and how they may be linked to disease is not understood.
“This study sheds much needed light on brain development in this crucial time period, and will hopefully spark further research in this area, and tell us more about the origins of serious mental health conditions such as schizophrenia.”
Whitaker, KJ, Vertes, PE et al. Adolescence is associated with genomically patterned consolidation of the hubs of the human brain connectome. PNAS; 25 July 2016; DOI: 10.1073/pnas.1601745113
Scientists have mapped the structural changes that occur in teenagers’ brains as they develop, showing how these changes may help explain why the first signs of mental health problems often arise during late adolescence.
Earlier this year, Toby Smith followed the moves of Disco Tony and his fellow cuckoos – a journey that took him to the forests of Gabon in West Africa and the fringes of the Batéké Plateau grasslands.
As a photojournalist – and first Leverhulme artist-in-residence at the University of Cambridge Conservation Research Institute (UCCRI) – his aim was both to photograph the landscape and to talk to the local villagers and hunters with whom the cuckoos share their home.
The result is a remarkable series of images that is providing bird researchers with a comprehensive idea of the rural landscapes in which the cuckoos overwinter.
The cuckoos all carry tiny lightweight devices that transmit a satellite-trackable signal as they make their arduous journey from breeding grounds in the UK south to Africa. Over the past five years, the signals of around 50 cuckoos have been helping a team of researchers at the British Trust for Ornithology (BTO) gain the first information on what happens to Africa-bound migrant birds after they have left the shores of the UK. The BTO’s hope is that this will help solve the mystery of why the cuckoo population has halved in the UK in the past 20 years.
Dr Chris Hewson, who leads the BTO project, explains: “Before we started the work, all we knew was that we were seeing a continual drop in cuckoo numbers. We didn’t know whether this was a result of changes in the UK breeding grounds, or of fatalities on the migration routes or in Africa. But, by tracking the birds, we now know which routes they take and the relative costs of each in terms of mortality, which has led us to begin to understand some of the causes of the decline.”
In fact the cuckoo is not alone in facing an uncertain future, says Juliet Vickery at the RSPB’s Centre for Conservation Science: “Around 70% of long-distant migrant bird species that winter in sub-Saharan Africa are declining. For most we don’t understand why, but the causes are likely to be complex as they face loss of habitat, through human- and drought-related land use change, hunting and climate change, right across the flyway.”
“We expect birds like cuckoos, swallows, swifts and nightingales to rock up here every summer but what if they don’t arrive?” adds Professor Bill Adams from the Department of Geography. Four years ago, he teamed up with Vickery, Hewson and researchers at the Department of Zoology to review all of the information available on the fate of the birds in a project funded by the Cambridge Conservation Initiative.
It became clear that really very little was known. In particular, there were few comparative studies on the effects of land use change in regions in Africa frequented by many of the 2.1 billion birds that migrate from Europe during the non-breeding season.
“These regions are areas where poverty makes the welfare of urban and rural people the policy priority,” adds Adams. “Often what is good news for people – adapting land to create work and food – is bad news for birds unless there is a sophisticated understanding of the implications of habitat requirements. Only then can we hope that decision making can support nature too.”
Adams and others view Africa as a major gap in knowledge about land use and birds: “In Europe we know a lot about how and why people use rural land, and what this means for migrant birds. But we don’t know much about rural African landscapes in which birds spend the winter.”
However, a few months ago, an idea began to take shape that could provide a step towards bridging this knowledge gap.
Smith had just taken up his role as artist-in-residence at UCCRI. Speaking to Adams and Hewson about the fate of the cuckoos, he was fascinated: “I wondered whether I could follow the cuckoos to Africa. No-one really knows what the cuckoo finds there – how people fashion a landscape that’s either friendly or unfriendly for cuckoos. I wanted to contribute to the research project by providing ‘eyes on the ground’ at their journey’s end.”
“The most important element in land use change in this region is the rural household,” explains Adams. “And the opportunity to present the landscapes in photographs that help us understand woodland management and agricultural practice was very attractive.”
Actually spotting a cuckoo, however, was unlikely, as Smith explains: “The tracking data is accurate enough to pinpoint where the cuckoos are to within 500 m, but there’s a delay between the signal being transmitted by the bird’s tag and being accessible to us in the field, and the forest terrain is vast.
“Seeing a bird would have been epic but, from a visual perspective, it wouldn’t have told us anything new. I wasn’t there as a birdwatcher, I was there as a documentary photographer. I was more interested in experiencing and engaging with the natural and social landscape of these birds. Very little scientific attention had been paid to this area – even Gabon’s most prolific birder hadn’t been there in 35 years.”
And so in January 2016, Toby Smith and Malcolm Green, an oral storyteller, arrived in Gabon with hammocks and a petrol stove, hired an off-road vehicle and set off to bush-camp for almost two weeks. Their trip was funded through Flight Lines (a joint project between the BTO and the Society of Wildlife Artists), the Economic and Social Research Council Impact Acceleration account, and Smith and Green themselves. They spoke to hunters and villagers, asking what they knew of the cuckoo – “we used photographs and bird-song recordings to help identify any interactions” – and Smith photographed the cuckoo’s habitat of forest margins and grasslands on the Batéké Plateau.
Back home, he opened up his photo editing and curating process to conservation specialists like Chris Hewson and other partners in the Cambridge Conservation Initiative – a unique collaboration between the University of Cambridge and biodiversity conservation organisations within the newly opened David Attenborough Building.
“Conservationists have a specific aesthetic interpretation of pictures, and so Chris and others needed to be really involved in the process of selecting which images told an important part of the cuckoo’s story.
“Generally, what I found in Gabon was encouraging. The density of people is so thin that even if the bird was hunted within 40 km of each village there are still huge areas available. It’s an area of great biodiversity and the villagers are not hugely aware of the cuckoo among the general flora and fauna.
“There was an incredible mosaic of gallery forest where the water table is accessible beneath the sand. And there were abrupt transitions between savannah landscape and forested landscape – there’s a lot of forest edge. From what we know about cuckoo behaviour this suits them to a T.”
“However, future land use change in the Gabon is likely to accelerate,” says Hewson. “To have Toby’s eye-witness account now is really important. Even finding that people rarely see cuckoos there is instructive for us – it shows what we are going to be up against when we go out there. It helps us to piece this together with knowledge of migration routes, to provide a more fully formed idea of what happens to the cuckoo for the major part of its annual cycle.”
Recently, the BTO tracking project has shown for the first time that cuckoos use two different routes to reach Africa (through Italy and across the Sahara, and through Spain and around the edge of West Africa) and that the Spanish route is associated with greater mortality. The team has found that the use of this route within local breeding populations correlates with population decline. In an article recently published in Nature Communications, the researchers suggest that this might be linked to severe droughts in Spain, such as in 2012, and raise concerns that a more recent drought in Italy might have further repercussions for the declining cuckoo population.
“Ultimately more research is vital,” says Adams, who has a joint project with Vickery starting next year in Ghana to look at the drivers of land use change and the impact on birds. “My hope is that Toby’s work will contribute towards a common understanding between ornithological researchers and development researchers about the way people and birds share landscapes.”
Meanwhile, as of March 2016, and after no signal for seven weeks, Disco Tony “popped back up” according to the BTO’s blog of each of the cuckoo’s whereabouts. Traced to the Central African Republic, he has begun his long journey back to the bog in Wales.
Why the name Disco Tony? The Welsh bog in which he was tagged was a particularly challenging environment to work in, with high tussocky grass. To reach the captured cuckoo, bird-ringer Tony Cross had to do a hopping, balancing, disco dance of a run. Naming the cuckoo Disco Tony seemed only appropriate.
Disco Tony has travelled over 5,000 miles. He is grey with a yellow ring around his eyes. He is a cuckoo, but not just any cuckoo. He is one of a very special group of birds whose every move is being monitored.
Researchers at King’s College London say they are able to predict educational achievement from DNA alone. Using a new type of analysis called a “genome-wide polygenic score”, or GPS, they analysed DNA samples from 3,497 people in the ongoing Twins Early Development Study. They found that people whose DNA had the highest GPS score performed substantially better at school. In fact, by age 16, there was a whole school-grade difference between those with the highest GPS scores and the lowest. The researchers herald their findings as a “tipping point” in the ability to use DNA – and DNA alone – in predicting educational achievement.
These findings will certainly generate debate, particularly about nature versus nurture. It’s a debate that forces us – often uncomfortably – to think about what makes us who we are. Are our careers, hobbies, food preferences, income levels, emotional dispositions, or even general success in life rooted in our genes (nature)? Or are we shaped more by our environment (nurture)? If it’s all down to our genes, what happens to the idea of determining our own destiny?
When it comes to the subject of intelligence, which today includes behavioural genetics research into “g (a measure of intelligence commonly used as a variable in research in this area) and cognitive ability, the nature-nurture debate becomes that much more heated.
There is a growing body of research that suggests intelligence is a highly heritable and polygenic trait, meaning that there are many genes that predict intelligence, each with a small effect size. While the connection between genetics research on educational achievement and findings on intelligence might not seem direct, studies like the one out of King’s establishes a biological connection between “g” and educational achievement. The findings mark the strongest genetic prediction for educational achievement so far, estimating up to 9% of variance in educational achievement at age 16.
But despite claims that this research moves “us closer to the possibility of early intervention and personalised learning”, there are important ethical concerns to take into account. For example, who would early intervention and personalised learning reach first? Is it possible parents with money, means, awareness and access would be first to place their children in “genetically sensitive schools” in the hope of getting an extra advantage?
It is not a secret that the history of intelligence research, and by extension genetics research on cognitive ability or educational achievement, is rooted in eugenics and racism, and has been used to validate the existence of racial and class differences. So how does this shameful past impact the field of behavioural genetics research today?
Many behavioural geneticists, like Robert Plomin, the senior author on the King’s study, believe the field has moved past this dark history and that the science is objective, neutral (as neutral as any research can be) and clear. The controversies that surround this research, at least in the eyes of Plomin and others, are fuelled by media sensationalism.
But many bioethicists and social scientists disagree with him. They argue that society values intelligence too much for this research to remain in neutral territory. Previously, the field was largely used to marginalise certain groups, particularly low-income or ethnic minority groups.
For some, attributing intelligence to genetics justifies the adverse circumstances many low-income and ethnic minority groups find themselves in; it wasn’t nurture that led to the under-performance of low-income or ethnic minority students in the classroom, it was nature, and nature cannot be changed. For bioethicists today, the question hanging over this branch of behavioural genetics is: who’s to say new research in this area won’t perpetuate the same social inequalities that similar work has done before?
Genetic research in an area once used to oppress people should openly acknowledge this past and explicitly state what its findings can and cannot prove (what many bioethicists call “trustworthy research”).
Stark class and race divides still persist in the UK and US, two countries where this branch of research is rapidly growing. While the study mentions the impact of a person’s place in society with educational achievement, it links this status back to genetics, highlighting the genetic overlap between educational achievement, g and family socioeconomic status.
The possibility that this kind of research may influence attitudes towards certain ethnic minorities and the less well off is real, as is the risk that this work might be used to justify social inequality. These concerns should be admitted and addressed by behavioural geneticists. The alternative could be a new form of eugenics.
The opinions expressed in this article are those of the individual author(s) and do not represent the views of the University of Cambridge.
Daphne Martschenko (Faculty of Education) discusses whether DNA can predict our educational achievement.
The University is one of only four higher education institutions in the UK to trial the new Tier 4 visa application pilot, which simplifies the visa process and extends post-study leave to six months.
Under the Home Office pilot launched on Monday, students applying for their visa will be required to submit fewer documents alongside their visa applications.
The two-year trial will apply for 2016/17 and 2017/18 entries, with the Home Office signaling it will publish its evaluation of the pilot in 2019.
All overseas applicants to Cambridge applying for a visa to undertake a Masters course of 13 months or less will automatically be considered under the scheme.
Though all students will be subject to Immigration Rules and undergo Home Office security and identity checks, they will no longer need to submit financial documents or their previous academic qualifications when applying for their visa.
The extension to students’ post-study leave means students who enrol on Master’s courses at Cambridge will have more time to find work after graduating and switch to a work visa, or to pursue further studies in the UK.
Anthony Dangerfield, Head of Cambridge’s International Student Team, said:
“We welcome any developments to the student visa system that support the University in attracting the brightest and best students from around the world.
“Those eligible under the pilot will have access to a streamlined visa application process and the additional time granted on the visa will be in helpful in supporting students who wish to seek employment opportunities in the UK after completion of studies.”
The Home Office has launched the pilot in order to test the benefits of a differentiated approach to the student visa system, to help ensure UK universities can maintain a highly competitive offer to international students.
After a two-year trial of the scheme, the Home Office Science (Migration and Border Analysis) will carry out an independent evaluation, examining management information and data from the participating universities. The evaluation will test the aims of the pilot and will report interim findings with a final report in the spring of 2019.
Detailed information about the pilot is outlined on the University’s student visa webpages at www.internationalstudents.cam.ac.uk/tier-4-visa-pilot
A pilot scheme to streamline the international student visa process could benefit more than 1,000 Masters students at the University of Cambridge each year.
Ever since a study back in 1953 discovered that London bus drivers were at greater risk of heart disease compared to bus conductors, scientists have found increasing evidence that lack of physical activity is a major risk factor for several diseases and for risk of early death. Recent estimates suggest that more than 5 million people die globally each year as a result of failing to meet recommended daily activity levels.
Studies in high-income countries have suggested that adults spend the majority of their waking hours sitting down. A typical day for many people is driving to work, sitting in an office, driving home and watching TV. Current physical activity guidelines recommend that adults do at least 150 minutes of moderate intensity exercise per week.
In an analysis published today in The Lancet that draws together a number of existing studies, an international team of researchers asked the question: if an individual is active enough, can this reduce, or even eliminate, the increased risk of early death associated with sitting down?
In total the researchers analysed 16 studies, which included data from more than one million men and women. The team grouped individuals into four quartiles depending on their level of moderate intensity physical activity, ranging from less than 5 minutes per day in the bottom group to over 60 minutes in the top. Moderate intensity exercise was defined as equating to walking at 3.5 miles/hour or cycling at 10 miles/hour, for example.
The researchers found that 60 to 75 minutes of moderate intensity exercise per day were sufficient to eliminate the increased risk of early death associated with sitting for over eight hours per day. However, as many as three out of four people in the study failed to reach this level of daily activity.
The greatest risk of early death was for those individuals who were physically inactive, regardless of the amount of time sitting – they were between 28% and 59% more likely to die early compared with those who were in the most active quartile – a similar risk to that associated with smoking and obesity. In other words, lack of physical activity is a greater health risk than prolonged sitting.
“There has been a lot of concern about the health risks associated with today’s more sedentary lifestyles,” says Professor Ulf Ekelund from the Medical Research Council Epidemiology Unit at the University of Cambridge. “Our message is a positive one: it is possible to reduce – or even eliminate – these risks if we are active enough, even without having to take up sports or go to the gym.
“For many people who commute to work and have office-based jobs, there is no way to escape sitting for prolonged periods of time. For these people in particular, we cannot stress enough the importance of getting exercise, whether it’s getting out for a walk at lunchtime, going for a run in the morning or cycling to work. An hour of physical activity per day is the ideal, but if this is unmanageable, then at least doing some exercise each day can help reduce the risk.”
The researchers acknowledge that there are limitations to the data analysed, which mainly came from participants aged 45 years and older and living in western Europe, the US and Australia. However, they believe that the strengths of the analysis outweigh these limitations. Most importantly, the researchers asked all included studies to reanalyse their data in a harmonized manner, an approach that has never before been adopted for a study of this size and therefore also provides much more robust effect estimates compared with previous studies.
Ekelund, U et al. Physical activity attenuates the detrimental association of sitting time with mortality: A harmonised meta-analysis of data from more than one million men and women. Lancet; 28 July 2016; DOI: 10.1016/S0140-6736(16)30370-1
The health risks associated with sitting for eight or more hours a day – whether at work, home or commuting – can be eliminated with an hour or more of physical activity a day, according to a study from an international team of researchers.
New research shows that natural accumulations of carbon dioxide (CO2) that have been trapped underground for around 100,000 years have not significantly corroded the rocks above, suggesting that storing CO2 in reservoirs deep underground is much safer and more predictable over long periods of time than previously thought.
These findings, published today in the journal Nature Communications, demonstrate the viability of a process called carbon capture and storage (CCS) as a solution to reducing carbon emissions from coal and gas-fired power stations, say researchers.
CCS involves capturing the carbon dioxide produced at power stations, compressing it, and pumping it into reservoirs in the rock more than a kilometre underground.
The CO2 must remain buried for at least 10,000 years to avoid the impacts on climate. One concern is that the dilute acid, formed when the stored CO2 dissolves in water present in the reservoir rocks, might corrode the rocks above and let the CO2 escape upwards.
By studying a natural reservoir in Utah, USA, where CO2 released from deeper formations has been trapped for around 100,000 years, a Cambridge-led research team has now shown that CO2 can be securely stored underground for far longer than the 10,000 years needed to avoid climatic impacts.
Their new study shows that the critical component in geological carbon storage, the relatively impermeable layer of “cap rock” that retains the CO2, can resist corrosion from CO2-saturated water for at least 100,000 years.
“Carbon capture and storage is seen as essential technology if the UK is to meet its climate change targets,” says lead author Professor Mike Bickle, Director of the Cambridge Centre for Carbon Capture and Storage at the University of Cambridge.
“A major obstacle to the implementation of CCS is the uncertainty over the long-term fate of the CO2 which impacts regulation, insurance, and who assumes the responsibility for maintaining CO2 storage sites. Our study demonstrates that geological carbon storage can be safe and predictable over many hundreds of thousands of years.”
The key component in the safety of geological storage of CO2 is an impermeable cap rock over the porous reservoir in which the CO2 is stored. Although the CO2 will be injected as a dense fluid, it is still less dense than the brines originally filling the pores in the reservoir sandstones, and will rise until trapped by the relatively impermeable cap rocks.
“Some earlier studies, using computer simulations and laboratory experiments, have suggested that these cap rocks might be progressively corroded by the CO2-charged brines, formed as CO2 dissolves, creating weaker and more permeable layers of rock several metres thick and jeopardising the secure retention of the CO2,” explains Bickle.
“However, these studies were either carried out in the laboratory over short timescales or based on theoretical models. Predicting the behaviour of CO2 stored underground is best achieved by studying natural CO2 accumulations that have been retained for periods comparable to those needed for effective storage.”
To better understand these effects, this study, funded by the UK Natural Environment Research Council and the UK Department of Energy and Climate Change, examined a natural reservoir where large natural pockets of CO2 have been trapped in sedimentary rocks for hundreds of thousands of years. Sponsored by Shell, the team drilled deep down below the surface into one of these natural CO2 reservoirs to recover samples of the rock layers and the fluids confined in the rock pores.
The team studied the corrosion of the minerals comprising the rock by the acidic carbonated water, and how this has affected the ability of the cap rock to act as an effective trap over geological periods of time. Their analysis studied the mineralogy and geochemistry of cap rock and included bombarding samples of the rock with neutrons at a facility in Germany to better understand any changes that may have occurred in the pore structure and permeability of the cap rock.
They found that the CO2 had very little impact on corrosion of the minerals in the cap rock, with corrosion limited to a layer only 7cm thick. This is considerably less than the amount of corrosion predicted in some earlier studies, which suggested that this layer might be many metres thick.
The researchers also used computer simulations, calibrated with data collected from the rock samples, to show that this layer took at least 100,000 years to form, an age consistent with how long the site is known to have contained CO2.
The research demonstrates that the natural resistance of the cap rock minerals to the acidic carbonated waters makes burying CO2 underground a far more predictable and secure process than previously estimated.
“With careful evaluation, burying carbon dioxide underground will prove very much safer than emitting CO2 directly to the atmosphere,” says Bickle.
The Cambridge research into the CO2 reservoirs in Utah was funded by the Natural Environment Research Council (CRIUS consortium of Cambridge, Manchester and Leeds universities and the British Geological Survey) and the Department of Energy and Climate Change.
The project involved an international consortium of researchers led by Cambridge, together with Aarchen University (Germany), Utrecht University (Netherlands), Utah State University (USA), the Julich Centre for Neutron Science, (Garching, Germany), Oak Ridge National Laboratory (USA), the British Geological Survey, and Shell Global Solutions International (Netherlands).
M. J. Bickle, et al. "Observational evidence confirms modelling of the long-term integrity of CO2-reservoir caprocks"Nature Communications 28 July 2016.
Study of natural-occurring 100,000 year-old CO2 reservoirs shows no significant corroding of ‘cap rock’, suggesting the greenhouse gas hasn’t leaked back out - one of the main concerns with greenhouse gas reduction proposal of carbon capture and storage.
New research on the financial practices surrounding a ‘wonder drug’ with a more than 90% cure rate for hepatitis C – a blood-borne infection that damages the liver over many years – shows how this medical breakthrough, developed with the help of public funding, was acquired by a major pharmaceutical company following a late-stage bidding war.
The research shows how that company more than doubled the drug’s price over original pricing estimates, calculating “how much health systems could bear” according to researchers, and channelled billions of dollars in profits into buying its own shares rather than funding further research.
In this way, the company, Gilead Sciences, passed significant rewards on to shareholders while charging public health services in the US up to $86k per patient, and NHS England almost £35k per patient, for a three month course of the drug.
The high prices have contributed to a rationing effect: many public systems across the US and Europe treat only the sickest patients with the new drug, despite its extraordinary cure rate, and the fact that earlier treatment of an infectious disease gives it less opportunity to spread.
Gilead’s strategy of acquisitions and buybacks is an example of an industry-wide pattern, say the researchers. Many big pharmaceutical companies now rely on innovation emerging from public institutes, universities, and venture-capital supported start-ups – acquiring the most promising drug compounds once there is a level of “certainty”, rather than investing in their own internal research and development.
The researchers, from Cambridge University’s Department of Sociology, say this effectively leaves the public “paying twice”: firstly for the initial research, and then for patent-protected high priced medications. A summary of their research has been commissioned by the British Medical Journal (BMJ) and is published today.
“Large pharmaceutical companies rarely take a drug from early stage research all the way to patients. They often operate as regulatory and acquisition specialists, returning most of the subsequent profits to shareholders and keeping some to make further acquisitions,” said lead researcher Victor Roy, a Cambridge Gates Scholar.
The study’s senior author, Prof Lawrence King, said: “Drug research involves trial and error, and can take years to bear fruit – too long for companies that need to show the promise of annual growth to investors, so acquisitions are often the best way to generate this growth.”
There are an estimated 150 million people worldwide chronically infected with hepatitis C. It disproportionately affects vulnerable groups such as drug users and HIV sufferers, and can ultimately lead to liver failure through cirrhosis if left untreated.
Roy and King’s article tells the story of the curative drug Sofosbuvir. The compound was developed by a start-up that emerged from an Emory-based laboratory that received funding from the US National Institutes of Health and the US Veterans Administration.
The start-up, Pharmasset, eventually raised private funding to develop sofosbuvir. When Phase II trials proved more promising than Gilead’s in-house hepatitis C prospects, it acquired Pharmasset for $11bn following a bidding war – the final weeks of which saw Pharmasset’s valuation rocket by nearly 40%.
“The cost of this late stage arms race for revenues has become part of the industry justification for high drug prices,” write Roy and King.
Once Sofosbuvir was market-ready in 2013, Gilead set a price of $84k. A US Senate investigation later revealed that Pharmasset had initially considered a price of $36k.
By the first quarter of 2016, Gilead had accumulated over $35bn in revenue from hepatitis C medicines in a little over two years – nearly 40 times Gilead and Pharmasset’s combined reported costs for developing the medicines.
Last year, Gilead announced that a lion’s share of those profits – some $27bn – will go towards ‘share buybacks’: purchasing its own shares to increase the value of the remaining ones for shareholders. By contrast, between 2013 and 2015 Gilead increased research investment by $0.9bn to $3bn total.
“Share buybacks are a financial manoeuvre that emerged during the early 1980s due to a change in rules for corporations by the Reagan administration. The financial community now expects companies to reward shareholders with buybacks, but directing profit into buybacks can mean cannibalising innovation,” said Roy.
A further example they cite is that of Merck, who spent $8.4bn in 2014 to acquire a drug developer specialising in staph infections. The next year they closed the developer’s early stage research unit, laying off 120 staff. Three weeks after that, Merck announced an extra $10bn in share buybacks.
In the BMJ article, the researchers set out a number of suggestions to counter the consequences of the current financial model. These include giving health systems greater bargaining power to negotiate deals for breakthrough treatments, and limiting share buybacks.
Roy and King also highlight a possible future model that uses a mix of grants and major milestone prizes to “push” and “pull” promising therapies into wider application, and, crucially, uncouples drug prices from supposed development costs, including those added by shareholder expectations. They write that this approach may be attempted for areas of major public health concern.
“The treatments for Hepatitis C may portend a future of expensive therapies for Alzheimer’s to many cancers to HIV/AIDS. Health systems and patients could face growing financial challenges,” said King.
“We need to recognise what current business models around drug development might mean for this future.”
An analysis of a new drug’s journey to market, published today in the BMJ, shines a light on financial practices that see some major pharmaceutical companies relying on a cycle of acquisitions, profits from high prices, and shareholder-driven manoeuvres that threatens access to medicines for current and future patients.
The University Library is celebrating its 600th anniversary with an exhibition of priceless treasures communicating 4,000 years of human thought. As part of the celebrations, they have commissioned six films on the six distinct themes featured in the exhibition Lines of Thought.
In the latest film, we travel from Darwin to DNA, demonstrating how Cambridge and the Cambridge collections have been crucial to the history of how we have understood heredity.
From Darwin’s provisional hypothesis of pangenesis to William Bateson’s work on animal variation, right the way through to Crick, Watson and Franklin, Cambridge has been at the forefront of understanding our place in the world.
Dr Alison Pearn, who curated the Darwin to DNA theme of Lines of Thought, said: “Darwin understood that natural variations, could over time, give rise to completely new forms and this is clearly demonstrated by the stuffed pigeons we have in the exhibition: the rock dove and the almond tumbler. The almond tumbler was one of Darwin’s favourite birds and you are able to see very clearly the differences between the two.
“We also have on display Darwin’s draft of the hypothesis of pangenesis, which is very much a tentative working idea for how variation might be passed on through generations. It’s a model for how inheritance might work.”
Other objects in the exhibition and film include a watercolour of Darwin staring at his ape predecessors in the Gallery of Ancestors, the working notes of Rosalind Franklin, and the 1905 letter by William Bateson where he first coins the term ‘genetics’ in its modern sense.
Added Pearn: “Bateson spent his career studying variation and said that the laws of inheritance would change man’s outlook on the world more than any advance in the history of knowledge. We are thrilled to have his work and so many other world-class exhibits on display at Cambridge University Library this year.”
Lines of Thought runs until September 30, 2016. Entry is free. To see the other films in the series, visit our YouTube channel.
Darwin’s stuffed pigeons, the letter which first coined the term ‘genetics’ and a paper by Crick and Watson which helped decode DNA all feature in the latest film to celebrate Cambridge University Library’s 600th anniversary.
The majority of the exhibits are from the Museum’s own rich collections, and those from the founding bequest of Viscount Fitzwilliam in 1816 can never leave the building and can only be seen at the Museum. For the first time, the secrets of master illuminators and the sketches hidden beneath the paintings will be revealed in a major exhibition presenting new art historical and scientific research.
Spanning the 8th to the 17th centuries, the 150 manuscripts and fragments in COLOUR: The Art and Science of Illuminated Manuscripts guide us on a journey through time, stopping at leading artistic centres of medieval and Renaissance Europe. Exhibits highlight the incredible diversity of the Fitzwilliam’s collection: including local treasures, such as the Macclesfield Psalter made in East Anglia c.1330-1340, a leaf with a self-portrait made by the Oxford illuminator William de Brailes c.1230-1250, and a medieval encyclopaedia made in Paris c.1414 for the Duke of Savoy.
Four years of cutting-edge scientific analysis and discoveries made at the Fitzwilliam have traced the creative process from the illuminators’ original ideas through their choice of pigments and painting techniques to the completed masterpieces.
“Leading artists of the Middle Ages and early Renaissance did not think of art and science as opposing disciplines,” said curator, Dr Stella Panayotova, Keeper of Manuscripts and Printed Books. “Instead, drawing on diverse sources of knowledge, they conducted experiments with materials and techniques to create beautiful works that still fascinate us today.”
Merging art and science, COLOUR shares the research of MINIARE (Manuscript Illumination: Non-Invasive Analysis, Research and Expertise), an innovative project based at the Fitzwilliam. Collaborating with scholars from the University of Cambridge and international experts, the Museum’s curators, scientists and conservators have employed pioneering analytical techniques to identify the materials and methods used by illuminators.
“This has been an exciting project,” said research scientist, Dr Paola Ricciardi. “By combining imaging and spectroscopic analysis — methods more commonly associated with remote sensing and analytical chemistry — and by exploring such a diverse range of manuscripts, we can begin to understand how illuminators actually worked.”
“A popular misconception is that all manuscripts were made by monks and contained religious texts, but from the 11th century onwards professional scribes and artists were increasingly involved in a thriving book trade, producing both religious and secular texts. Scientific examination has revealed that illuminators sometimes made use of materials associated with other media, such as egg yolk, which was traditionally used as a binder by panel painters.”
Other discoveries include pigments rarely associated with manuscript illumination – such as the first ever example of smalt detected in a Venetian manuscript. Smalt, obtained by grinding blue glass, was found in a Venetian illumination book made c.1420. Evidently, the artist who painted it had close links with the famed glassmakers of Murano. This example predates by half a century the documented use of smalt in Venetian easel paintings.
Analyses of sketches lying beneath the paint surfaces, and of later additions and changes to paintings help to shed light on manuscripts and their owners. One French prayer book, made c.1430, was adapted over three generations to reflect the personal circumstances and dynastic anxieties of a succession of aristocratic women.
Adam and Eve were originally shown naked in an ABC commissioned c.1505 by the French Queen, Anne of Brittany (1476-1514) for her five-year-old daughter. However, a later owner, offended by the nudity, gave Eve a veil and Adam a skirt. Infrared imaging techniques and mathematical modelling have made it possible to reconstruct the original composition without harming the manuscript.
The Museum’s treasures will be displayed alongside carefully selected loans — celebrated manuscripts from Cambridge libraries as well as other institutions in the UK and overseas. These include an 8th century Gospel Book from Corpus Christi College, the University Library’s famous Life of Edward the Confessor, magnificent Apocalypses from Trinity College and Lambeth Palace, London, and a unique model book from Göttingen University.
Visitors will be encouraged to make their own discoveries in the exhibition galleries and online through a new, free digital resource: ILLUMINATED: Manuscripts in the Making. With hundreds of high resolution digital images and infrared photographs, this interactive, cross-disciplinary resource offers users in-depth information on the manuscripts’ contents, patrons, cultural and historical contexts, as well as scientific data relating to artists’ techniques and materials.
With over 300 illustrations in full colour, the authoritative exhibition catalogue encompasses subjects as diverse as the trade in pigments, painting techniques, the medieval science of optics and modern-day forgeries. Catalogue entries and essays by leading experts offer readers insight into all aspects of colour from the practical application of pigments to its symbolic meaning.
“We are delighted to be presenting this exhibition in our bicentenary year,” said director, Tim Knox. “Ten years ago The Cambridge Illuminations was the Museum’s first ever record-breaking exhibition, attracting over 80,000 visitors. People were enchanted by the remarkable beauty and delicacy of the manuscripts. I am convinced that our bicentenary visitors will again be equally inspired by the superb illuminations collected and treasured at the Fitzwilliam for 200 years, and will value this rare opportunity to find out how they were made and how we are preserving them for the future.”
COLOUR: The Art and Science of Illuminated Manuscripts will run during the second half of the Fitzwilliam’s bicentenary year, from 30 July to 30 December 2016. Admission is free.
Some of the finest illuminated manuscripts in the world – treasures combining gold and precious pigments – will go on display today in celebration of the Fitzwilliam Museum’s bicentenary.
Visions of the Great White South opens at Bonhams in Bond Street on August 2 and uses collections from the fateful Terra Nova expedition, held by the Scott Polar Research Institute at the University of Cambridge.
The British Antarctic Expedition, better known by the name of its ship the Terra Nova, took place from 1910-1913. Captain Robert Falcon Scott appointed Dr Edward Wilson, a close friend and a fine watercolourist, as his chief scientist. He also invited camera artist Herbert Ponting to join the expedition as official photographer; a bold move in an era when high quality photography required great skill and careful attention in ordinary circumstances, let alone in the extreme environment of the Antarctic. Both Wilson and Ponting captured expedition life as well as keeping a visual record of scientific phenomena that the crew were studying.
Making use of the Scott Polar Research Institute’s historical collections, the exhibition will also show examples of Captain Scott’s photography from the expedition in a series of beautiful new platinum prints of his work, produced by Belgian photographic publishers Salto Ulbeek in collaboration with the Scott Polar Research Institute. Scott was taught photography by Ponting during the expedition, and, in the images he produced, the influence of both Ponting and Wilson can be discerned in the ways he captured the vast and compelling landscapes of the Antarctic.
Both Ponting and Wilson hoped to hold a joint exhibition. However, the catastrophic loss of the South Pole party including Scott and Wilson made that impossible.
Owing to the death of Dr. Wilson his pictures could never be reproduced for sale, as he had intended. His widow, therefore, considered it better that they should be exhibited separately. The whole beautiful series of his water colours was shown at the Alpine Club, whilst my photographs were exhibited at the Fine Art Society's galleries, London.
Professor Julian Dowdeswell, Director of the Scott Polar Research Institute, said: “It is a great privilege to hold the remarkable paintings of Edward Wilson and the striking photography of Herbert Ponting in the Scott Polar Research Institute’s historic collection. By reuniting their work in this special exhibition we are pleased to give the public the opportunity to see their works together and at their best.”
Alongside the historic artworks, visitors will have the opportunity to see contemporary interpretations of the ‘great white south’. For several years the Friends of Scott Polar Research Institute, with the support of Bonhams and the Royal Navy, have run an artist-in-residence scheme which sends an artist to the Antarctic on board the icebreaker HMS Protector. Artists including Captain Scott’s grand-daughter Dafila Scott and renowned wildlife artist Darren Rees will exhibit their responses to the frozen wilds of Antarctica.
Robert Brooks, Chairman of Bonhams, said: “It is an honour for Bonhams to exhibit the art of two such extraordinarily talented and brave men and to be able to hang works together publicly for the first time ever. The Terra Nova expedition is famous, of course, for the tragic loss of Captain Scott and his companions. But its purpose was primarily scientific and Wilson and Ponting's work reminds us of the pioneering quest for knowledge that underpinned the venture."
The chairman of the Friends of Scott Polar Research Institute, Rear Admiral Nick Lambert, said: “The Friends are extremely grateful for Bonhams’ and the Royal Navy’s ongoing support of the Artist in Residence Programme enabling five artists to experience and record Antarctica’s fabulous environment hosted by HMS Scott and HMS Protector over the past five years. The exhibition is a brilliant opportunity to display modern works alongside those of the Terra Nova expedition.”
The Friends are also pleased to announce that this summer their first Arctic artist-in-residence will be travelling to Svalbard, with the support of One Ocean Expeditions.
A new exhibition has reunited the iconic photography of Herbert Ponting with the watercolours of Edward Wilson – more than a century after the two Antarctic explorers first dreamt up their plan for a joint exhibition.
To date, researchers have identified hundreds of genetic variants that increase or decrease the risk of developing diseases from cancer and diabetes to tuberculosis and mental health disorders. However, for the majority of such genes, scientists do not yet know how the variants contribute to disease – indeed, scientists do not even understand how many of the genes function.
One such gene is C13orf31, found on chromosome 13. Scientists have previously shown that variants of the gene in which a single nucleotide – the A, C, G and T of DNA – differs are associated with risk for the infectious disease leprosy, and for the chronic inflammatory diseases Crohn’s disease and a form of childhood arthritis known as systemic juvenile idiopathic arthritis.
In a study published today in the journal Nature Immunology and led by the University of Cambridge, researchers studied how this gene works and have identified a new mechanism that drives energy metabolism in our immune cells. Immune cells help fight infection, but in some cases attack our own bodies, causing inflammatory disease.
Using mice in which the mouse equivalent of the C13orf31 gene had been altered, the team showed that the gene produces a protein that acts as a central regulator of the core metabolic functions in a specialist immune cell known as a macrophage (Greek for ‘big eater’). These cells are so named for their ability to ‘eat’ invading organisms, breaking them down and preventing the infection from spreading. The protein, which the researchers named FAMIN (Fatty Acid Metabolic Immune Nexus), determines how much energy is available to the macrophages.
The researchers used a gene-editing tool known as CRISPR/Cas9, which acts like a biological ‘cut and paste’ tool, to edit a single nucleotide in the risk genes within the mouse’s genome to show that even a tiny change to our genetic makeup could have a profound effect, making the mice more susceptible to sepsis (blood poisoning). This showed that FAMIN influences the cell’s ability to perform its normal function, controlling its capacity to kill bacteria and release molecules known as ‘mediators’ that trigger an inflammatory response, a key part of fighting infection and repairing damage in the body.
Professor Arthur Kaser from the Department of Medicine at the University of Cambridge, who led the research, says: “By taking a disease risk gene whose role was completely unknown and studying its function down to the level of a single nucleotide, we’ve discovered an entirely new and important mechanism that affects our immune system’s ability to carry out its role as the body’s defence mechanism.”
Dr Zaeem Cader, the study’s first author, adds: “Although it’s too early to say how this discovery might influence new treatments, genetics can provide invaluable insights that might help in identifying potential drug targets for so-called precision medicines, tailored to an individual’s genetic make-up.”
The research was largely funded by the European Research Council and the Wellcome Trust, with support from National Institute for Health Research (NIHR) Cambridge Biomedical Research Centre.
Cader, MZ et al. C13orf31 (FAMIN) is a central regulator of immunometabolic function. Nature Immunology; 1 Aug 2016; DOI: 10.1038/ni.3532
A new mechanism that affects how our immune cells perform – and hence their ability to prevent disease – has been discovered by an international team of researchers led by Cambridge scientists.
Short-faced dogs such as pugs, bulldogs (known as English bulldogs in the US) and French bulldogs are among the cutest pets out there – they’re the very reverse of the wolves they descended from. Over the last few years these breeds have become increasingly common, partly thanks to advertising and their popularity among celebrities. In fact all three breeds are now in Britain’s top ten favourite dogs.
But these dogs are the result of an amazing transformation in appearance and temperament caused by selective breeding, which has come at quite a cost to the dogs' health. Around half of them have breathing problems that sometimes lead to overheating, exercise intolerance and sleep apnoea. Their large heads and narrow pelvises also cause problems in giving birth (forcing Caesarean sections for many if not most) and their skin folds can become infected. Their exposed eyes are also vulnerable to damage, with about 15% suffering prolapsed third eyelids and many having other types of eye damage. Quite a number of dogs in several of the breeds also succumb to back or hip problems.
So research geneticists have started to look at ways to reduce the intrinsic health problems of these breeds. A recent investigation of genetic variation in bulldogs showed that all the individuals examined had little genetic diversity in either paternal or maternal lines. The same was true for the diversity of some types of immune system genes, so that the ability of these bulldogs to respond to pathogens may be reduced, which may potentially also be connected to common allergies in this breed. The authors argued that the breed’s health could only be restored by breeding dogs with other breeds, rather than preserving the breed in its current closed state.
With colleagues including Jane Ladlow, Lajos Kalmar and Nai-chieh Liu, I have been doing both genetic and clinical analyses of bulldogs and other short-faced breeds. Working with breeders of bulldogs, we investigated the respiratory distress that many of these dogs suffer from. We started by developing a computer algorithm to interpret breathing traces taken from dogs at rest, allowing us to objectively identify the disease and quantify variation between individuals. This analysis, together with collection of DNA samples from the studied dogs, opened the way for accurate genetic analyses of the respiratory disease. On the way, we also gained information on the genetic health of the breeds we studied as a whole.
Our findings agree with those of the new study in suggesting that the best way of breeding back to a less extreme skull shape would be to introduce dogs from outside the current breed registers. This is likely to be true of many other aspects of conformation and temperament. And we would agree that the extreme changes in appearance (such as the excessive skin rolls in these breeds) do account for many of their disease problems.
An alternative to outbreeding?
Fortunately not all short-faced dogs suffer from the respiratory disorder and although our research is not yet complete, we now have pretty strong evidence that there are still multiple genetic variations between those that do and those that don’t. But we do not know whether this is also true for other aspects of conformation and appearance-related conditions.
We believe that the swiftest way to remove these diseases would be to outbreed to a dog type that does not have the features that cause the health problems typical of these breeds.
Over the last few years groups such as the (now disbanded) Advisory Council on the Welfare Aspects of Dog Breeding, the RSPCA, a number of dog welfare charities and the Associate Parliamentary Group on Animal Welfare have offered a lot of advice about the health problems of these dogs in an attempt to reduce their popularity. Yet the kind of expensive advertising campaign that could really reach the public has been lacking.
An additional problem is that most breeders reject the introduction of genes from outside their breed. They fear the breed will “be contaminated”, that new diseases will be introduced and that the breed will lose its character or change in temperament. There appears to be no likelihood of legislation to compel breeders to outbreed on welfare grounds.
But with the help of our research it may be possible to breed for healthier dogs using the existing genetic variation within the breed (in addition to contributions from crosses outside the breed if necessary and if they can be made acceptable to breeders). If within-breed crosses to reduce disease do prove practical, this will probably be a slower route to reduce the disease burden for an individual offspring than an outcross-breed. However, the advantage is that within-breed crosses are likely to be widely accepted by dog breeders and so it may prove a quicker way of moving the whole population forward towards better breed health.
The opinions expressed in this article are those of the individual author(s) and do not represent the views of the University of Cambridge.
David Sargan (Department of Veterinary Medicine) discusses the health implications of breeding the perfect pets.
Earlier this year, scientists used zebra finches to pinpoint the gene that enables birds to produce and display the colour red.
Now, a new study shows the same ‘red gene’ is also found in turtles, which share an ancient common ancestor with birds. Both share a common ancestor with dinosaurs.
The gene, called CYP2J19, allows birds and turtles to convert the yellow pigments in their diets into red, which they then use to heighten colour vision in the red spectrum through droplets of red oil in their retinas.
Birds and turtles are the only existing tetrapods, or land vertebrates, to have these red retinal oil droplets. In some birds and a few turtle species, red pigment produced by the gene is also used for external display: red beaks and feathers, or the red neck patches and rims of shells seen in species such as the painted turtle.
The scientists mined the genetic data of various bird and reptile species to reconstruct an evolutionary history of the CYP2J19 gene, and found that it dated back hundreds of millions of years in the ancient archelosaur genetic line - the ancestral lineage of turtles, birds and dinosaurs.
The findings, published today in the journal Proceedings of the Royal Society B, provide evidence that the ‘red gene’ originated around 250 million years ago, predating the split of the turtle lineage from the archosaur line, and runs right the way through turtle and bird evolution.
Scientists say that, as dinosaurs split from this lineage after turtles, and were closely related to birds, this strongly suggests that they would have carried the CYP2J19 gene, and had the enhanced ‘red vision’ from the red retinal oil.
This may have even resulted in some dinosaurs producing bright red pigment for display purposes as well as colour vision, as seen in some birds and turtles today, although researchers say this is more speculative.
“These findings are evidence that the red gene originated in the archelosaur lineage to produce red for colour vision, and was much later independently deployed in both birds and turtles to be displayed in the red feathers and shells of some species, going from seeing red to being red,” says senior author Dr Nick Mundy, from the University of Cambridge’s Department of Zoology.
“This external redness was often sexually selected as an ‘honest signal’ of genuine high quality in a mate,” he says.
The previous research in zebra finches showed a possible link between red beaks and the ability to break down toxins in the body, suggesting external redness signals physiological quality, and there is some evidence that colouration in red-eared terrapins is also linked to honest signalling.
“The excellent red spectrum vision provided by the CYP2J19 gene would help female birds and turtles pick the brightest red males,” says Hanlu Twyman, the PhD student who is lead author on the work.
The structure of retinas in the eye includes cone-shaped photoreceptor cells. Unlike mammals, avian and turtle retinal cones contain a range of brightly-coloured oil droplets, including green, yellow and red.
These oil droplets function in a similar way to filters on a camera lens. “By filtering the incoming light, the oil droplets lead to greater separation of the range of wavelengths that each cone responds to, creating much better colour sensitivity,” explains Mundy.
“Humans can distinguish between some shades of red such as scarlet and crimson. However, birds and turtles can see a host of intermediate reds between these two shades, for example. Our work suggests that dinosaurs would have also had this ability to see a wide spectrum of redness,” he says.
Over hundreds of millennia of evolution, the CYP2J19 gene was independently deployed to generate the red pigments in the external displays of some bird species and a few turtle species. The scientists say their data indicate that co-option of CYP2J19 for red colouration in dinosaurs would also have been possible.
The ancestral lineage that led to scaly lizards and snakes split from the archosaur line before turtles, and, as the findings suggest, before the origin of the red gene. These reptiles either lack retinal oil droplets, or have yellow and green but not red.
However, the crocodilian lineage split from the archelosaur line after turtles, yet crocodiles appear to have lost the CYP2J19 gene, and have no oil droplets of any colour in their retinal cones.
Mundy says there is some evidence that oil droplets were lost from the retinas of species that were nocturnal for long periods of their genetic past, and that this hypothesis fits for mammals and snakes, and may also be the case with crocodiles.
A gene for red colour vision that originated in the reptile lineage around 250m years ago has resulted in the bright red bird feathers and ‘painted’ turtles we see today, and may be evidence that dinosaurs could see as many shades of red as birds - and perhaps even displayed more red than we might think.