In Nature this week, a team led by Max Planck Institute researchers report on the sequencing of the genome of a Neanderthal woman from Denisova Cave in the Altai Mountains of Siberia. The DNA was obtained from a bone of an adult female who is thought to be about 50,000 years old. The scientists' analysis indicated that woman’s parents were closely related — possibly half-siblings or an uncle and niece — and that such mating among close relatives was not uncommon among her recent ancestors. Comparison of the genomic data with a low-coverage genome from a Neanderthal from the Caucasus region and with 25 present-day human genomes reveals several low-level gene-flow events among Neanderthals, Denisovans, and early modern humans, and suggest that several hominin groups frequently interbred during the Late Pleistocene, between about 12,000 years and 126,000 years ago.
Also in Nature, University of Pittsburgh researchers publish data showing that the deadly North American eastern equine encephalitis virus — an RNA virus spread by mosquitos — uses a microRNA to suppress viral replication inside host immune cells, thereby inhibiting immunity. The discovery gives clues as to why the virus is so lethal. "We propose that RNA viruses can adapt to use antiviral properties of vertebrate miRNAs to limit replication in particular cell types and that this restriction can lead to exacerbation of disease severity," the researchers add.