Claire Asher

Nature

World’s biggest plant shrinks as hungry deer move in

A vast aspen grove that is renowned as one of the world’s biggest living organisms is shrinking as a result of human activity and browsing deer.

One aspen tree can sprout thousands of genetically identical trunks to form a single, sprawling clone known as a ‘forest of one tree’. The biggest known clone is the Pando, a quaking aspen (Populus tremuloides) in Utah that covers 43 hectares and is thought to have survived for thousands of years.

Nature

Tapeworm DNA hints at discomforts of life in a medieval trading hub

Centuries-old cesspits reveal that residents of a bustling port in medieval Germany were infested with a diverse range of parasitic worms — suggesting that trade helped to carry the worms far and wide. Intestinal parasites such as tapeworms and roundworms were common in Europe before the advent of modern sanitation. Adrian Smith at the University of Oxford, UK, and his colleagues extracted DNA from parasite eggs in soil samples...

Nature

Virus that robs parrots of their plumage has spread around the globe

A virus that can inflict feather loss and severe beak deformities on infected parrots is widespread in the wild. Infections with beak and feather disease virus, which can cause lethal illness, are common in captive cockatoos, parakeets and other types of parrot. But how far the virus, which originated in Australasia, has spread in wild bird populations has been a mystery.

Nature

The world’s first flexitarian shark grazes like a cow

Sharks are notorious carnivores, but one small hammerhead shark also feels the need to eat its greens. Bonnethead sharks (Sphyrna tiburo) live in seagrass meadows in the shallow waters off the coasts of the Americas. In addition to consuming invertebrates such as squid, they have been observed eating large amounts of seagrass. But whether the animals digest this dietary plant matter has been a mystery. Samantha Leigh at the University of California, Irvine, and her colleagues fed five captive...

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A river runs through it — and keeps the Amazon’s bird species diverse

A new genetic analysis shows that rivers in northeast South America rarely give rise to new bird species, but are important in maintaining existing biodiversity. Researchers found that 86 pairs of the more than 400 endemic bird species in the Rio Negro basin have range boundaries that meet but never overlap, many of them coinciding with either the Rio Negro or the Rio Branco. Amazonian rivers, they conclude, can play two distinct roles in species evolution: their formation may separate popula...

Nature

Sex hormones in age-old mammoth hair hint at pregnancy

Testosterone has been extracted from the hair of Siberian woolly mammoths, including two females whose hormone levels suggest that they may have been pregnant.
The remains of mammoths are often found embedded in ice and permafrost, which preserves the extinct animals’ DNA so well that scientists can sequence it. To investigate whether chilled remains could yield other important molecules, Lee Koren at Bar Ilan University in Ramat Gan, Israel, and her colleagues set out to extract testosterone...

Science

A new pesticide may be as harmful to bees as the old one

Bees around the globe are in trouble, and many scientists worry that a common pesticide bears some blame. Now, scientists have shown that a chemical hailed as a potential replacement has similar harmful effects, reducing the number of new queens and males in bumblebee colonies. The finding could force farmers to seek alternative solutions to reduce crop damage from insect pests.

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Trase.earth tracks commodities, links supply chains to deforestation risk

Launched in 2016, Trase is an innovative Internet tool, available to anyone, which tracks commodities supply chains in detail from source to market, and can also connect those chains to environmental harm, including deforestation. Until the advent of Trase, knowledge of supply chains was sketchy and difficult to obtain.
The Trase Yearbook 2018 is the first in an annual series of reports on countries and companies trading in such commodities as soy, sugarcane and maize, which also assesses the...

Nature

Why spit is key to building a butterfly

Moths and butterflies assemble their tube-like mouth parts with help from a self-made material: spit. The tubular proboscis that moths and butterflies use to sip nectar develops in two halves, which join up after the insects become adults. How an adult keeps these structures from falling apart as they interlock, however, has long puzzled scientists.

Nature

Eye evolution came easy for simple sea creatures

Jellyfish and their kin have no brains and make do with rudimentary nervous systems. But an analysis now shows that these simple sea creatures evolved eyes multiple times, transforming basic precursor cells into a wide range of useful visual systems. Using DNA sequences, Natasha Picciani and Todd Oakley at the University of California, Santa Barbara, created an evolutionary tree of Cnidaria, the large grouping — or phylum — that includes jellyfish, sea anemones and corals.

Nature

American dogs arrived domesticated in the New World

Domestic dogs probably first arrived in North America with early human settlers from Siberia, only to be wiped out by Europeans half a millennium ago.
Using genome sequences from archaeological remains and modern breeds, Laurent Frantz at the University of Oxford, UK, and his colleagues constructed an evolutionary tree for dogs. They found that the earliest dogs in North America were not domesticated from local wolves, but probably arrived alongside humans who migrated there between 17,000 an...

Nature

Koala genome reveals secrets to surviving a deadly diet

Koalas feed almost exclusively on eucalyptus leaves, which are fragrant but toxic. Now, genomic data reveal how these unusual creatures thrive on a diet that would kill many mammals.

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Plant response to rising CO2 levels may alter rainfall patterns across tropics

Increasing greenhouse gases in the atmosphere could dry out the Amazon and drench Indonesia, all because rising carbon dioxide levels in the air are changing how plants breathe, according to new research published in Nature Climate Change. James Randerson and Gabriel Kooperman at the University of California, Irvine and colleagues investigated how the physiological response of trees to rising atmospheric greenhouse gas levels affect the output of global climactic models.

The Scientist

Artificial Intelligence to Boost Liquid Biopsies

Machine-learning algorithms tuned to detecting cancer DNA in the blood could pave the way for personalized cancer care. Modern cancer medicine is hampered by two big challenges—detecting cancers when they are small and offering cancer patients personalized, dynamic cancer care. To find solutions, several academic labs and biotech firms are turning to artificial intelligence, working to develop machine-learning algorithms that could help decipher weak signals in the blood that can identify cancer...