What evidence do MPs turn to when they make policy?

Anyone going to mention RCTs today? PA/PA Wire

MPs value the views of constituents and expert opinion more highly than evidence from randomised controlled trials, a new survey has found. However, the majority of the 104 Labour and Conservative MPs from the previous parliament who were questioned support the idea of using randomised controlled trials to evaluate policies and don’t believe they are too expensive.

The survey, conducted by Ipsos MORI and the charitable trust Sense about Science, also found that MPs were more inclined to act on their own principles than on the results of randomised controlled trials, which involve testing new interventions on a randomly selected group of people and comparing that with a control group of people who get the usual intervention.

Interestingly, the survey found that the views of experts and the opinions of constituents trumped those of practitioners, such as teachers or doctors. It also found that MPs give very little weight to the views of journalists.

There are signs that a lot of MPs harbour some erroneous misgivings about randomised controlled trials, suggesting a widespread lack of understanding of how the trials work and how they might be used to test the effectiveness of policies.

Many thought it unfair that some people would be randomly assigned to not receive the policy being investigated – 35% believed this, including 26% of the 74 MPs who supported the use of the trials. But this is a fundamental principle, and a strength, of this kind of trial.

The MPs quizzed were roughly as supportive of pilot schemes without a comparison group as they were for randomised controlled trials by 67% to 64%, misunderstanding the value that the addition of a randomly selected control group can bring.

Pilot studies also contain an aspect of “unfairness”, for people in areas where the scheme is not piloted. But pilot studies do not have the added benefit of collecting data in those areas to provide a comparison, generating stronger evidence as to whether a policy is effective.

Each word in the name RCT is important. Randomisation of the trial’s subjects mean that, in a health trial for example, there’s less chance of the sickest people being all in one group and warping the findings. Controlled studies compare the new treatment to a baseline group where the usual treatment is given to check whether there’s a real difference between the two. And they are a trial, rather than just implementing a new treatment without testing it first.

What’s important for MPs

The survey also highlighted the difference between where politicians think they should look for evidence when making policy decisions, and what evidence they have actually used to justify the decisions they’ve made in the past. Randomised controlled trials were rated as less important than uncontrolled pilot trials in both instances.

MPs put more trust in their own principles than RCTs. Ipsos MORI

Evidence from experts was voted top of what politicians felt they should consider, but this was beaten by “the views of constituents” when they were asked what they have used to justify a policy in the past. In both instances, the MPs' own principles were rated much higher than evidence from RCTs.

Political decisions will rarely be based on evidence alone. And it should absolutely be the case that politicians want to listen to their constituents and act accordingly. But where the impact of a potential policy change is not known, testing this out before it is widely implemented can save money long-term, and make sure only policies likely to be effective are implemented.

Although the background of the MPs surveyed is not reported, an interest in and understanding of science is somewhat lacking in the corridors of power. In 2010, the Campaign for Science and Engineering compiled a list of MPs with an interest or background in science, and it equated to roughly 10% of MPs in parliament at that time. The implication here is that the other 90% have little or no interest in science whatsoever, let alone a scientific background or understanding of its methods.

Randomised trials gaining ground

In medicine it seems obvious to test treatments before rolling them out, and there is a move to apply such techniques to policy too, aided by RCTs. In 2013, the then secretary of state for education, Michael Gove, enlisted the help of epidemiologist Ben Goldacre to help bring a strong evidence base to educational policy.

The Behavioural Insights Team work with the government to design and test policies or interventions, and along with Goldacre and David Torgerson have authored a policy paper called Test, Learn, Adapt, instructing how to run trials for policy.

The Behavioural Insights Team have already used randomised controlled trials to investigate the effectiveness of a number of policy changes or interventions. One such trial showed that a small change to a government website led to increases in organ donation sign-up.

A government-backed charity called the Educational Endowment Foundation have used randomised trials to show that teaching assistants can improve numeracy and literacy when used effectively, which had been doubted after evidence from earlier largely non-randomised research. Goldacre has himself said that if anyone wants to help bring RCTs to policymaking, he will “stand on the barricades” with them.

The results of this new survey suggest MPs would be receptive to this. Rather than smirking at politicians' failure to grasp the complexities of scientific trials, researchers need to explain their importance, design and limitations. Randomised controlled trials have changed medicine for the better, and if done properly can do the same for the way policies are developed.

MPs don’t need a scientific background to value evidence-based policy, but if they need help understanding how to get the strongest evidence, we should provide it.

State of the Nation: government protection of the science budget has come at a cost

Funding, steady as she goes. notes Alessandro Storniolo/Shutterstock.com

Science and research were not at the front of the political debate in 2010. The first coalition government for a generation was cobbled together in the middle of a global economic recession and a domestic banking crisis which combined to put public spending under pressure.

The formal coalition agreement made only fleeting reference to university research. But the Conservative and Liberal Democrat parties comprising the coalition made more detailed statements in which they expressed support for science. Has the past five years of government lived up to these signals? Certainly the government has protected and even expanded science funding in the face of public spending cuts in most other areas. But achieving that outcome involved a hard ride through a land of smoke and mirrors, and the support has come with strings attached.

I don’t cling to every syllable uttered by politicians. They need the freedom to try out ideas and allow policy to evolve, with manifestos the place where the outcomes of those trials appear. The Campaign for Science and Engineering (CaSE) invited the leaders of three political parties to set out their plans for science in more detail shortly before the 2010 election. The responses to this request were duly published and I treat them as equivalent to manifesto commitments.

During the election campaign, there was close alignment on science between the Liberal Democrats and the Conservatives. The Lib Dems were bolder and more explicit in their spending promises but it was clear that, like the Conservatives, they were approaching public finances with caution.

Leaving scientists to choose priorities

The coalition partners agreed that, with some specific exceptions, academic research should be prioritised by researchers. Some minor infringements of this long-standing Haldane Principle by the previous administration made it an election issue. This principle – under which the government outlines research areas of strategic interest and leaves the details up to academics – might seem arcane, but adhering to it has underpinned the UK’s outstanding science and research performance. Most major economies spend more of their national income than the UK on science. Indeed, the UK’s science spending is mediocre by international standards. But not many countries share the ruthlessly meritocratic process by which the UK research community selects its projects, and only the US outperforms this country in terms of scientific excellence.

UK punches above its weight considering the amount it spends on science. Graeme Reid/OECD, Author provided

Perhaps because this was a cost-neutral policy commitment, the independence of science found its way into the coalition agreement:

We will ensure that public funding mechanisms for university research safeguard its academic integrity.

Before the end of 2010, Ministers David Willetts and Vince Cable had jointly published a “clarifying” statement, which explained:

Decisions on individual research proposals are best taken by researchers themselves through peer review. The Coalition government supports this principle as vital for the protection of academic independence and excellence. We all benefit from its application in the UK.

Protecting investment in science

The previous Labour government had been strong supporters of science, with funding growing via a ten-year science and innovation policy developed by the then chancellor Gordon Brown and science and innovation minister David (Lord) Sainsbury. While researchers kept quiet during the election campaign there was unease over the prospect of funding cuts as the country entered an era of austerity.

As newly appointed ministers soon discovered, many researchers across medicine, the environment, the arts, agriculture, engineering and economics joined together when threatened with cuts. High-profile global corporations made it clear that the UK’s strong research base was one reason they invested here. Charities expressed fears that science cuts would undermine their relationships with donors and universities.

Science budgets have not fallen over five years, relatively speaking. Graeme Reid/HM Treasury, Author provided

In an effort to stimulate growth and build confidence in a flagging economy, the coalition latched onto strong evidence of science as an engine of growth. Science funding bodies sought more social and economic impact from the fruits of UK research, an agenda that was gaining prominence coincidentally just as it was needed. Protecting science funding was about more than just calming the academic community: it was about the future of the economy. David Willetts was already a fan of blue-skies research, and by connecting science to the economic agenda he won George Osborne’s support and enthusiasm. This crystallised in the October 2010 Spending Review. While most government departments faced 20% cuts, Osborne announced:

A ring fence will be maintained to ensure continuity of investment in science and research… To support long term growth, the government will prioritise support for world class science [and] maintain resource spending in cash terms.

The cuts affecting other departments had been dodged and a ringfence placed around £4.6 billion each year for science and research until 2015. A wonderful outcome for science. Then we read the small print.

The small print

First, the good news applied only to recurrent expenditure. This meant researchers salaries and project funding remained intact but the annual rate of capital investment was to be cut by almost 40% by 2015, reducing investment in science research facilities by £1.5 billion. The long-term nature of capital investment increased the effect of this sudden withdrawal – having taken into account existing commitments to capital investment, there was hardly any money for new facilities.

It also emerged that the protected part of the budget would be stretched to cover costs of the UK Space Agency, which had previously been funded from elsewhere. There were also cuts of 40% (or “cumulative real growth of -40%”, as the review put it) to administration budgets over the five year parliament.

Marrying science to the economy

By 2011 it was clear that the economic downturn was stubborn. The government was looking for new ways to kickstart growth without leaving its policy of fiscal restraint. A desire to avoid recreating a finance-centric, London-focused economy as existed before the crash led to frequent speeches about improving the diversity of the economy and re-balancing it regionally beyond the southeast.

But what could government actually do to stimulate long-term growth and high quality jobs? How about making capital investments in science and research? That’s a good idea.

So in the March 2011 budget the chancellor announced new investments in high-performance computing, space technology and research campuses in Edinburgh, Oxfordshire, Norwich and Cheshire – details specified by ministers, albeit on scientific advice. More were announced in the autumn statement later that year.

In the 2012 budget there was a further emphasis on science, with the chancellor creating the £100m Research Partnership investment Fund (RPIF) for businesses and charities to invest alongside universities in major scientific facilities. Successive budgets and autumn statements followed a similar theme, with the 2015 budget including the announcement of the Alan Turing Institute at the British Library in London.

More cash, but at a price

Direct capital investment from government has made good the 2010 cuts and increased the annual rate of investment to £1.1 billion, some 20% higher in cash terms than in 2010. It has also committed to maintain that level until the end of the next Parliament in 2020-21. RPIF alone has led to more than £1 billion investment in scientific infrastructure, two-thirds of which comes from businesses and charities. This scheme has been extended until at least 2017 so we can expect even more of these investment partnerships.

This adds up to substantial investment in modern scientific facilities with higher levels of ministerial engagement in priority-setting and specifying the locations for facilities around the UK. In effect the science community was offered money – lots of it – at a time of public spending cuts in return for accepting closer ties to political priorities. This is not blunt political direction of science but nor is it the full independence to which the science community had grown accustomed.

So where are we now? Funding for scientific research projects is still based on merit and managed by independent peer review. The level of this recurrent funding has remained fixed since 2010, as per signals from the coalition on entering office. Of course the spending power of that funding has been eroded by inflation. This raises questions about how the operation of new capital facilities are going to be funded.

Lord Krebs, until recently chairman of the House of Lords Select Committee on Science and Technology, described a “damaging disconnect” between recurrent budgets and capital investments. Along with CaSE, Krebs is among those calling for a long term science funding strategy and greater transparency in the decisions involved. This would give researchers the opportunity to plan for the future, increase the appeal of UK science to business and charity partners, and offer attractive career options to ensure a continued stream of talented new scientists and researchers.

The outgoing government seemed to recognise this issue in its Plan for Growth: Science and Innovation published at the end of last year. Whether the next government will continue this approach is something we will shortly discover.t

The famous olive trees of Puglia are ravaged by disease – here's how we can save them

The whole olive-growing region of Puglia has been devastated. olive grove by risteski goce/www.shutterstock.com

A common, humble field bug is spreading a disease that has already infected millions of olive trees in Italy. Olive and citrus fruit crops throughout the Mediterranean are threatened, yet there has been a collective failure to recognise the danger and take decisive action.

In Puglia in southeastern Italy, 241,000 hectares of olive groves have been restricted, with at least 10% of the 11m olive trees in the worst-affected region, Lecce, infected by the Xilella fastidiosa bacterium. The disease has almost entirely wiped out the region’s olive trees in the two years since it was first detected, and threatens the olive crop elsewhere in the country.

Olive trees often hundreds of years old are completely destroyed by the wasting disease, which leaves them looking dehydrated as if burnt. The disease has spread at epidemic levels – quickly, and with devastating effect. Besides the great economic damage, olive trees are a tremendous cultural symbol of the region, and their loss is a huge blow to the region’s identity. There’s also a convincing argument that the epidemic will spread to neighbouring regions in Italy, and on to other parts of the Mediterranean. So interested countries such as France and Greece are demanding Italy take rapid steps to control the disease, before it gets worse.

Slash and burn

Yet so far the only real action taken has been to apply the European Union protocol that requires the destruction of any olive tree and vegetation for a mile around the border of the affected zone, in this case the Salentinian Peninsula. Will this stop the diffusion of Xilella? The bacterium spreads easily as it cleverly uses a partner, the burrowing meadow spittlebug (Philaenus spumarius), one of the most abundant field insects, in order to enter the tree.

Olive trees are often hundreds of years old. fotometin

The border management strategy so far reported by the Italian and EU authorities offers only tentative steps to limit the spread of the pathogen. It’s very hard to see that this will have any significant effect: the spittlebugs are not great flyers but can be carried many kilometres in a single day by the wind or on humans or animals. Officials have also discussed an export ban on the plants, but total control is quite impossible in a region where olive trees are so important.

I was consulted immediately after the disease was discovered, but various proposals to tackle the infection were rejected in favour of a policy that only followed the EU protocol, which we know to be ineffective. Since then I and many other researchers have worked in the lab to test other solutions.

More than just pesticide

Pesticides have performed an invaluable service around the world, preventing crop losses to various insect pests, and controlling the spread of insect-borne diseases such as malaria, dengue, or yellow fever. But there are several chemicals that are no longer effective due to growing resistance – from microorganisms developing resistance to antibiotics, to insects becoming resistant to insecticides. It’s possible that in the next 20 to 30 years all the currently used pesticides will have lost their effectiveness.

It’s possible to attack the bacterium by treating the olive trees with antibiotics, but this is extremely expensive and too complicated to administer to so many trees. The spittlebugs can be controlled by insecticide — in fact the bug’s larval stage is the best route, as it’s possible to apply insecticide before they have grown wings to fly. But current chemicals are not useful, so we are working on a new line of insecticides based on natural products to tackle the Xilella problem.

Three-point plan needed

The olive tree’s disease has three main players, the bacterium, the insect, and probably a symbiotic fungus of which we understand very little, in addition to the olive plant itself. They work together, acting like a “superorganism”. It is a very complex system, but in some way also very efficient.

The only way to face the Xilella challenge is integrated pest management, tackling all elements at once. A soil treatment to sustain the plant, a larvicidal insecticide to control the spittlebug, an antifungal treatment, and a natural, low-cost and eco-friendly antibiotic to treat the plant to help prevent infection from becoming established. It’s vital that we act strongly and soon, as the disease has already spread far.

Finally, perhaps the biggest challenge will be to gain the active cooperation of the local population and farmers, who so far have only suffered damage from the loss of their trees, and for whom the idea of slashing and burning millions of century-old trees is positively sacrilegious – even if it may be the best course of action in the long term.

In flight refuelling for airliners will see non-stop services shrink the globe

Is this the future for non-stop, long-haul flights? IIAF

There’s real pressure on the aviation industry to introduce faster, cheaper and greener aircraft, while maintaining the high safety standards demanded of airlines worldwide.

Airlines carry more than three billion passengers each year, which presents an enormous challenge not only for aircraft manufacturers but for the civil aviation infrastructure that makes this extraordinary annual mass-migration possible. Many international airports are close to or already at capacity. The International Air Transport Association (IATA) has estimated that, without intervention, many global airports – including major hubs such as London Heathrow, Amsterdam Schiphol, Beijing and Dubai – will have run out of runway or terminal capacity by 2020.

The obvious approach to tackling this problem is to extend and enlarge airport runways and terminals – such as the long-proposed third runway at London Heathrow. However there may be other less conventional alternatives, such as introducing in-flight refuelling for civil aircraft on key long-haul routes. Our project, Research on a Cruiser-Enabled Air Transport Environment (Recreate), began in 2011 to evaluate whether this was something that could prove a viable, and far cheaper, solution.

Aircraft weight-watchers

The world’s first in-flight refuelling in 1923. AF.mil

If in-flight refuelling seems implausible, it’s worth remembering that it was first trialed in the 1920s, and the military has continued to develop the technology ever since. The appeal is partly to reduce the aircraft’s weight on take-off, allowing it to carry additional payload, and partly to extend its flight range. Notably, during the Falklands War in 1982 RAF Vulcan bombers used in-flight refuelling to stage what was at the time the longest bombing mission ever, flying 8,000 miles non-stop from Ascension Island in the South Atlantic to the Falklands and back.

Reducing take-off weight could offer many benefits for civilian aircraft too. Without the need to carry so much fuel the aircraft can be smaller, which means less noise on take-off and landing and shorter runways. This opens up the network of smaller regional airports as new potential sites for long-haul routes, relieving pressure on the major hubs that are straining at the seams.

There are environmental benefits too, as a smaller, lighter aircraft requires less fuel to reach its destination. Our initial estimates from air traffic simulations demonstrate that it’s possible to reduce fuel burn by up to 11% over today’s technology by simply replacing existing global long-haul flight routes with specifically designed 250-seater aircraft with a range of 6,000nm after one refuelling – roughly the distance from London to Hong Kong. This saving could potentially grow to 23% with further efficiencies, all while carrying the same number of passengers the same distance as is possible with the current aircraft fleet, and despite the additional fuel burn of the tanker aircraft.

Imagine if these Tornado fighter jets were 250-seater passenger aircraft and you’ve got the idea. Suzanne M Jenkins/USAF

However, this is not the whole picture – in-flight refuelling will require the aerial equivalent of petrol stations in order to deliver keep passenger aircraft in the sky. With so much traffic it simply wouldn’t be possible to refuel any aircraft any time, anywhere it was needed. The location of these refuelling zones, coupled with the flight distance between the origin and destination airports can greatly affect the potential benefits achievable, possibly pulling flights away from their shortest route, and even making refuelling on some routes impossible – if for example the deviation to the nearest refuelling zone meant burning as much fuel as would have been saved.

Safety and automation

As with all new concepts – particularly those that involve bringing one aircraft packed with people and another full of fuel into close proximity during flight – it’s quite right to ask whether this is safe. To try and answer this question, the Dutch National Aerospace Laboratory and German Aerospace Centre used their flight simulators to test the automated in-flight refuelling flight control system developed as part of the Recreate project.

One simulator replicated the manoeuvre from the point of view of the tanker equipped with an in-flight refuelling boom, the other simulated the aircraft being refuelled mid-flight. Critical test situations such as engine failure, high air turbulence and gusts of wind were simulated with real flight crews to assess the potential danger to the operation. The results were encouraging, demonstrating that the manoeuvre doesn’t place an excessive workload on the pilots, and that the concept is viable from a human as well as a technical perspective.

So far we’ve demonstrated the potential aerial refuelling holds for civilian aviation, but putting it into practice would still pose challenges. Refuelling hubs would need to be established worldwide, shared between airlines. There would need to be fundamental changes to airline pilot training, alongside a wider public acceptance of this departure from traditional flight operations.

However, it does demonstrate that, in addition to all the high-tech work going into designing new aircraft, new materials, new engines and new fuels, the technology we already have offers solutions to the long-term problems of ferrying billions of passengers by air around the world.

You could lose your job to a computer, so why isn't the digital economy an election issue?

All digitalled up with nowhere to plug. Crown Copyright

There seems to be a uniform impression among British politicians and legislators that the digital economy will radically transform the country for the better. A recent House of Lords select committee report on the digital economy highlighted the perils of failing to respond adequately to the opportunities it provides for future prosperity.

Why then, if the digital economy is so central to the future, is it being given so little attention during this election campaign?

The committee recommended increasing the speed and extent of broadband provision, and improving access to the internet. It’s difficult to discern the political parties’ precise approach to the digital economy until they launch their manifestos. However, looking back to the 2010 election campaign Labour, Conservatives and Liberal Democrats all agreed that developing physical broadband infrastructure was the main priority – this is not a contentious issue.

Skills, but not only skills

There are other aspects of the report that are contentious. The committee recommended extremely ambitious steps for near-universal provision of training in digital skills, despite many of the experts giving evidence to the committee arguing that basic literacy and numeracy were more important. Indeed, the speed with which computer hardware and software develops means that specific technical skills can quickly become obsolete – cognitive skills that support adapting to rapid change are arguably of more benefit in the digital economy.

There is a broader concern about the impact of automation on job security, something the committee dealt with only superficially. While acknowledging that up to 35% of jobs could disappear due to automation, it argued that these would be in low-skilled occupations.

The suggestion is that this potential loss of employment will be offset by more, higher-level jobs in the knowledge economy, no doubt filled by those workers who have honed their skills in the proposed digital skills training programmes to be offered. But, as author and Silicon Valley entrepreneur Martin Ford asserts, it is arguably knowledge workers whose jobs are as much at risk, if not primarily so, from computerisation.

Three parties, no answers

And where do the main parties stand on these issues? The Labour Party’s independent review of the impact of the digital economy on the nation’s creative industries released its report on March 27. It’s difficult to find within it any significant differences from the policies of the present government – particularly in respect of leaving unchanged UK copyright and intellectual property law.

But there is recognition of some of digital economy’s negative social effects, with recommendations to boost women’s representation in the digital creative industries, and new powers to tackle the online monopolies that are a tendency of some digital markets. While this does not represent official party policy, it’s a good indication of policy under a Labour government.

All quiet on the Westminster front, when digital economy is up for discussion. Crown Copyright/BBC

The Conservatives’ approach to the digital economy can be gleaned from the evidence provided by two ministers of state, Ed Vaizey and Nick Boles, to the Lords review. They emphasised the importance of skills-based training, much of which could be undertaken by the private sector. Also emphasised was the need to increase the number of people studying science, technology, engineering and maths at university – especially women. But the tension between the Conservatives’ promotion of free market economics and its desire for state intervention to ensure domestic security runs through the party’s approach to the digital economy. Look for example at the enormous criticism from across the tech sector of David Cameron’s wrong-headed suggestion of “banning encryption”.

The whole picture

It’s wise to highlight the great growth potential of the digital economy in the face of such political ambivalence, as per comments on the recent leaders' debate. But the other political and social implications of an increasingly digital economy need to be addressed too. For example, the mountains of e-waste from electronic devices rendered quickly obsolete, and the environmental impact of huge datacentres that power an internet economy. Yet a written submission to the committee on the digital economy’s environmental footprint was simply ignored.

The report also fails to address the sexism that runs through much of the tech industry and is evident in online communities. Dealing with the under-representation of women in these industries requires a little more sophistication than simply urging more of them to study science and engineering subjects. The tendency towards a “winner takes all” outcome in digital industries – where in an online, instantly-global market the best product wins and little is left for others (Facebook’s dominance is the classic example) – also requires some creative thinking.

As the committee’s report suggested, a much more wide-ranging and all-encompassing approach is required in order to harness the benefits of the digital economy, and to predict and prevent its potential drawbacks. This should be an approach that draws on the perspectives of the technology, arts and humanities sectors too – not just a footnote to a narrow skills-based agenda. So far, none of the parties give the slightest impression of being up to the task.

Tyrannosaurs fought and ate each other

Tyrannosaurs, shown in this artist’s illustration, both hunted for food and scavenged, which is probably how bite marks ended up on the skull of a young Daspletosaurus unearthed at Canada’s Dinosaur Provincial Park.

© Tuomas Koivurinne

The Cretaceous period was a tyrannosaur-eat-tyrannosaur world. Bite marks from before and after death scar the skull of an ancient tyrannosaur called Daspletosaurus, researchers report April 9 in PeerJ.

Paleontologists identified a fossilized skull and jaw as that of a teenage Daspletosaurus, a cousin to Tyrannosaurus rex. Some pre- and postmortem marks on the bones correspond to bite marks — big enough to come from the teeth of a Daspletosaurus or another tyrannosaur. The marks could be evidence of both combat and cannibalism, the scientists conclude.

It’s not unheard of for tyrannosaurs to fight or eat each other, but understanding the prevalence of such behavior lends insight into the extinct reptiles’ ecology.

Genome sequencing mountain gorillas reveals the genetic impact of inbreeding

Not a happy cousin. Gorilla Tracking , CC BY

Our genetic cousins, mountain gorillas, have been the subject of ongoing conservation efforts for decades. Despite this there are fewer than 900 left in the wild because of poaching and habitat destruction. Now, genetic sequencing has revealed the toll these constant threats have taken on their genome.

Our research, published in Science, reveals a striking loss of genetic diversity, but also finds more to be optimistic about than expected.

Man-made threats

Gorillas are classified into two species: one in West Africa (Gorilla gorilla) and one to the east (Gorilla beringei) in the centre of the continent. Mountain gorillas are a subspecies of the eastern gorilla species, and differ from the others in that their habitat ranges to high altitudes. This has consequences for their diet and physiology – for example, they have thicker and longer fur, which helps them survive the colder temperatures and the wetter, mistier environment.

The number of mountain gorillas living in the Virunga volcanic mountain range (on the borders of Rwanda, Uganda and the Democratic Republic of Congo) dropped to around 253 in 1981. Since then, conservation efforts have bolstered numbers there to approximately 480. There is another colony of about 400 of mountain gorillas about 30 km to the north. This adds up to only around 880 mountain gorillas surviving in the wild.

Our new research is based on blood samples collected from wild-born gorillas and is the first whole genome study; previous studies have used DNA from fecal samples or looked at much smaller sequences.

Chronic decline

Analysis of the genome data revealed that as well as suffering a dramatic collapse in numbers during the last century, mountain gorillas had already experienced a long decline going back many thousands of years. These events have resulted in a very substantial loss of genetic diversity and more inbreeding than expected: it turns out that two mountain gorillas are typically identical at more than a third of their genetic sequence – the comparable number for most humans is only a few percent.

Inbreeding increases the threat from disease and environmental change by reducing mountain gorillas' ability to adapt. It also means they carry a larger burden of harmful mutation than other gorilla species.

Silver lining

However there is a silver lining: many of the most severely harmful mutations are less common in mountain gorillas than in other gorilla subspecies, and appear to have been purged. These are mutations that disrupt the operation of a gene by prematurely terminating the protein it produces. Such mutations are expected to be more problematic than other others which may only alter the protein slightly, and some of them will be very harmful or even lethal if the protein is doing an essential job in the body.

To see why severely harmful mutations can be reduced as a result of inbreeding, consider that in a large population someone carrying such a mutation is less likely to meet and have children with another carrier. The mutation is able to persist because we have two copies of every gene, meaning it is usually only present in one copy in offspring. The lethal effect is masked by a working copy and can be passed on. However in an inbred population, carriers are more likely to meet others with the same mutation, meaning their children are more likely to have two copies, with lethal consequences for the children and preventing the mutation from being passed on.

As great apes, mountain gorillas are close evolutionary cousins of humans, so understanding their evolution also provides some insights into our own. For example, it is believed that our own ancestors also experienced severe reductions in population size at least once during human evolution, and other close relatives such as the Neanderthals went extinct in this way. Mountain gorillas thus provide an opportunity to study how humans might have adapted genetically to this condition.

Justice for poachers

It is also hoped that the detailed, whole-genome sequence data gathered through this research will aid conservation efforts in a practical way. Now that a genome-wide map of genetic differences between populations is available, it will be possible to identify the origins of gorillas that have been illegally captured or killed. This will enable more gorillas to be returned to the wild and will make it easier to bring prosecutions against those who poach gorillas for souvenirs and bush meat.

So, despite the threats they face, there are reasons to be optimistic about the future for mountain gorillas, if conservation efforts can be sustained and further encroachment on their habitat resisted. This research suggests that although low in genetic diversity, they have not yet crossed a point of no return. They can continue to survive and will return to larger numbers if we help them.