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This Week in PNAS: Jun 21, 2016

Editor's Note: Some of the articles described below are not yet available at the PNAS site, but they are scheduled to be posted some time this week. 

In the early, online edition of the Proceedings of the National Academy of Sciences, researchers from China, Israel, the US, and the Czech Republic find evidence for sympatric speciation in the blind mole rat, Spalax galili, in Israel. The team did transcriptome sequencing on blind mole rats from neighboring populations in Israel's Galilee Mountains that live in sites with distinct rock, soil, and vegetation features. From SNP, gene expression, microRNA, and other patterns detected in blind subterranean rodents from each site, the study's authors saw signs of reproductive isolation between the blind mole rats from the chalk or basalt sites, apparently due to natural selection. Moreover, they say, "[b]ecause sharply divergent geological, edaphic, climactic, and biotic interfaces about in nature, we conclude that [sympatric speciation] may be a common model of the origin of new species, as envisaged by Darwin."

A team from the US, Sweden, and Switzerland searches for clues to the population history of the Tibetan plateau through low-coverage genome sequencing and mitochondrial genome sequencing on ancient remains from eight individuals, obtained from the Nepal's Annapurna Conservation Area. The samples, which stretch back between 1,250 years and 3,150 years, represent individuals from periods with three different material cultures. By comparing sequences from the ancient individuals with one another and with sequences for individuals from more than two dozen populations profiled by the 1000 Genomes Project, the researchers found that the high-altitude adapted populations in the Himalayan arc have East Asian ancestry and relatively stable genetic profiles over time.

Researchers from the US and Japan say they've found evidence for epigenetic alterations in the oxytocin gene OXT that mediates sociability. The team tested more than 100 adult volunteers from the University of Georgia, combining brain imaging, behavioral questionnaires, and personality tests with a methylation assay on DNA obtained from participants' saliva samples. Results from the analysis hinted that decreased methylation in the promoter region of OXT tended to coincide with sociability features — from the ability to recognize emotion in other people's faces to more secure attachment styles.