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This Week in PLOS: Aug 24, 2015

A PLOS Genetics paper by researchers in UK, Australia, and Ethiopia suggests the Ari Blacksmith population in Ethiopia shares relatively recent ancestry with Ethiopia's Ari Cultivators. Through a re-analysis of genome-wide data for 237 individuals from populations in Ethiopia, Somalia, and South Sudan, coupled with information on nearly 900 individuals tested through the 1,000 Genomes or HapMap projects, the team found that the socially marginalized Ari Blacksmith group descended from the same population as Ari Cultivators, but experienced a recent population bottleneck. "[O]ur results are consistent with the start of genetic isolation between Blacksmiths and Cultivators corresponding roughly to a time period near the introduction of blacksmithing in the region," the authors say, noting the results "serve as a cautionary tale for over-interpreting clustering … plots or results from other unsupervised learning techniques."

In PLOS Neglected Tropical Diseases, French researchers describe results from a head-to-head comparison of metagenomic 16S ribosomal RNA gene sequencing and RNA sequencing for characterizing microbes carried by rodent populations and finding potential bacterial pathogens. The team did RNA-seq and 16S metagenomic sequencing on pooled RNA samples from the spleens of 190 French voles. For the most part, the approaches each picked up similar bacterial representatives, though 21 of the 45 potential vole pathogens were missed with 16S metagenomic sequencing on one of the sequencing platforms. On the other hand, the study's authors note that "only the 16S approach was able to determine bacterial diversity in each individual, which then permitted the derivation of bacterial prevalence and interaction patterns within host populations."

A dengue virus strain circulating in two regions in southwest Bhutan appears to have originated in India, according to a molecular epidemiological analysis by a team from Thailand and Bhutan. As they report in another PLOS Neglected Tropical Diseases paper, the researchers used a combination of ELISA and nested RT-PCR assays to test blood samples from 379 individuals in southern Bhutan who were suspected of having dengue infections. Based on a phylogenetic analysis of molecular patterns in the 119 confirmed dengue virus infection cases, the study's authors found that the prominent dengue virus serotype strains in Bhutan tended to be most closely related to dengue viruses found in northern India.