Skip to main content
Premium Trial:

Request an Annual Quote

This Week in PNAS: Apr 16, 2019

Researchers from the University of California, Davis, the University of Connecticut, and elsewhere attempt to tease out natural selection signals in Indigenous populations in Alaska, the US Southeast, and central Mexico. With genotyping arrays, the team profiled genome-wide SNP patterns in 150 individuals from Indigenous populations, using the variant patterns to explore the individuals' ancestry and search for potential signs of selection that were shared or distinct between populations. "We find evidence for adaptation to cold and high latitudes in an Alaskan population, whereas infectious disease was a strong selective pressure in the southeastern United States and central Mexico," they write. "Because there are few shared signals of selection between populations, these sweeps likely occurred after population differentiation in the Americas."

An international team led by investigators at Sweden's Uppsala University explore population and social structures at several Stone Age burial sites in Europe, focusing on burial sites marked by megalith structures. Based on genome sequence data for two dozen ancient individuals at megalithic burial sites in Ireland, Scotland, and Sweden, along with genomes for three ancient individuals in Scotland and the Czech Republic without megalithic burials, the researchers suggest that the megalithic tombs were often used by related individuals with genetic ties to the farming groups found in the same areas at that time. And in the British Isles, at least, men appeared to be over-represented in megaliths, the authors note, with these and other findings hinting that "at least some of these funerary monuments were used by patrilineal societies."

Researchers in China and the US propose a microRNA-based approach for repairing and regenerating lung tissue following a stint of bacterial pneumonia caused by Streptococcus pneumoniae. In a mouse model of S. pneumoniae, the team used quantitative RT-PCR to assess a miRNA called miR-302 seemed to turn up at higher-than-usual levels in alveolar epithelial cells from bouncing back from the acute inflammation and damage caused by the bacterial infection. Based on these results, the authors attempted to boost post-pneumonia alveolar epithelial cell regeneration in infected mice using an in vivo treatment made up of miR-302 mimics. "Although this approach … will not curtail infection per se, it reduces suffering and shortens recovering time by fostering tissue repair," the authors write.