One of Earth’s rarest fish, the Devil’s Hole pupfish, is often cited as an unusual example of a small but long-lasting population of animals. But these fish may not have been isolated for as long as once thought.

Less than 100 adult pupfish (Cyprinodon diabolis, pictured) live in a small pool in the southwestern United States, and they have supposedly been there for 10,000 to 20,000 years. Michael Reed at Tufts University in Medford, Massachusetts, and Craig

Stockwell at North Dakota State University in Fargo analysed genetic data from C. diabolis, along with their numbers over time. They concluded that the fish have been living in this pool for only a few hundred to a few thousand years, and will probably become extinct within the next 400 to 3,000 years.

This means that C. diabolis is no exception to the rule that small, isolated populations cannot persist for long.Proc. R. Soc. B 20141648 (2014)

Z O O L O G Y

Clock ticks for tiny group of fish

E C O L O G Y

Boring invaders held at the borderInsect traps near busy ports could provide crucial early warnings of the arrival of invasive tree-boring beetles.

These pests can damage forests and can travel around the world hidden in wood. So Davide Rassati and his colleagues at the University of Padua in Legnaro, Italy,

laid out

S T E M C E L L S

Cord-blood cells made plentifulA group of small molecules can spur the growth of stem cells from umbilical cord blood. These could one day be used as transplants to treat, for example, certain blood cancers.

Guy Sauvageau at the University of Montreal in Canada and his colleagues screened a library of small molecules for ones that stimulate the proliferation of human cord-blood stem cells that drive the long-term production of all blood cells. They found one molecule that worked particularly well and synthesized an optimized version, UM171, that performed even better. This molecule triggered the expansion of cord-blood stem cells that, when transplanted into mice, generated the full array of mature blood cells.

Cord-blood stem cells could be an alternative to bone-marrow transplants, which are currently in short supply, the authors say. Science 345, 1509–1512 (2014)

V I R O L O G Y

Flu virus comes in various flavoursThe proteins that make up the influenza viral particle differ depending on which species the virus was generated in.

The composition of a virus is important for its ability to infect and spread. Edward Hutchinson, Ervin Fodor and their colleagues at the University of Oxford, UK, used mass spectrometry to identify and quantify the proteins in seven different flu viruses derived from either mammalian tissue or chicken

bait to lure the beetles into traps at 15 Italian ports and in the surrounding forests. They caught 14 alien species, including Cordylomera spinicornis (pictured), along with native beetles from the Scolytinae, Cerambycidae and Buprestidae families, including four species never before found in Italy. The number of alien species correlated with the volume of imports at the ports.

The authors suggest that traps in busy ports could help the fight against these economically damaging invasive pests.J. Appl. Ecol. http://doi.org/vrj (2014)

eggs. The authors found a common core architecture of proteins, but some components were unique to the host.

The finding suggests that flu vaccines grown in chicken eggs or mammalian tissue could have different compositions.Nature Commun. 5, 4816 (2014)

C A N C E R I M M U N O L O G Y

Therapy broadens immune responseA drug that activates the immune system against a type of skin cancer does so by promoting new immune responses to cancer, rather than

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M AT E R I A L S

Squid skin inspires colourful display A flexible material can display patterns much in the same way that cuttlefish, octopuses and squid (pictured) form colourful spots in their skin.

To quickly change their appearance and camouflage themselves, such cephalopods use their muscles to stretch and relax small sacs of pigment under their skin. A team led by Xuanhe

G E N O M I C S

Mutation has big disease effectA genetic mutation is associated with a change in a person’s risk of heart disease from high to low — one of the first rare gene variants found, by sequencing large numbers of people, that has a sizable impact on disease risk.

Nicole Soranzo of the Wellcome Trust Sanger Institute in Hinxton and Nicholas Timpson of the University of Bristol, both in the United Kingdom, led a team that sequenced the genomes of 3,202 Europeans with known levels of blood triglycerides — fatty acids linked to increased risk of heart disease. They discovered that one variant of the APOC3 gene, found in less than 0.2% of the study participants, was associated with reductions in triglyceride levels that they estimated were large enough to significantly lower an

C H E M I S T R Y

On the trail of a drug in plantsThe painkiller tramadol is not made naturally by plants despite last year’s surprising finding that the drug was present in the roots of a Cameroonian plant (Nauclea latifolia).

Michael Spiteller from the Technical University of Dortmund in Germany and his team analysed plant, water and soil samples in Cameroon and interviewed local residents to track down the true explanation. Farmers in the far north area have been giving tramadol to their cattle, which then excrete the drug and its metabolites into soil and water. The painkiller is subsequently absorbed by plant roots.

The authors say this off-label use of tramadol poses a risk to health because it also contaminates local water supplies. Angew. Chem. Int. Ed. http://doi.org/f2t7tg (2014)

Q U A N T U M O P T I C S

Photons made to dance together Physicists have made two beams of light interact at the level of individual photons.

Getting photons to interact is important for all-optical computation and for producing new quantum states of light. Kristin Beck at the Massachusetts Institute of Technology in Cambridge and her colleagues crossed two beams of light inside a cavity filled with trapped and cooled caesium atoms. When photons from each beam tried to pass through the system at the same time, the trapped atoms changed their internal state, allowing only one photon to be transmitted, while the other one was reflected or scattered.

The interaction creates two entangled beams of light, which the authors say could eventually be used to improve the accuracy of measurements, such as of a gyroscope’s rotation, that would otherwise be limited by the laws of quantum mechanics. Phys. Rev. Lett. 113, 113603 (2014)

Zhao of the Massachusetts Institute of Technology in Cambridge developed an artificial equivalent using silicone rubber and organic compounds called spiropyran mechanophores, which glow when exposed to force. The researchers control the display by applying an electric field to deform the silicone, causing the mechanophores to glow in various repeated patterns including lines, circles and letters.

The display size and resolution could be scaled up for use as a camouflaging coating, the authors say.Nature Commun. 5, 4899 (2014)

How to draw perfect figuresJumbled charts and misleading graphs — illustrations in a paper can go wrong in many ways. Now, a treatise that attempts to rescue science from bad figures has been getting rave reviews on social media.

Using original illustrations — some elegant, some clunky — to prove key points, ‘Ten simple rules for better figures’ tries to steer researchers away from common pitfalls. The first tip: know your audience. A stripped-down graph that might make sense to your closest colleagues could prove baffling to anyone else. Many researchers on social media were grateful for the advice. Andrew Jackson, an evolutionary ecologist at Trinity College Dublin, tweeted: “Magic. Using that in lectures for sure. Incoming students take note!” PLoS Comput. Biol. 10, e1003833 (2014)

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individual’s risk level. The results support the

idea that sequencing large populations can uncover rare genetic mutations that have a major impact on disease risk.Nature Commun. 5, 4871 (2014)

amplifying pre-existing ones.The melanoma drug

ipilimumab boosts the activity of immune-system cells called T cells, which recognize a variety of molecules on tumour cells, marking them for destruction. Pia Kvistborg and Ton Schumacher of the Netherlands Cancer Institute in Amsterdam and their team compared T cells from melanoma patients before and after treatment and found that the drug broadened the range of melanoma targets recognized by T cells. But melanoma-specific T cells that were already present before treatment did not expand their ranks, suggesting that the drug stimulates new responses.

Boosting the range of T cells could be a useful strategy for other cancer immunotherapies, the authors say.Sci. Transl. Med. 6, 254ra128 (2014)

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