In PLOS Genetics, an international team led by investigators in China and the US describes hypoxia-related genetic adaptations it detected in Tibetan grey wolves living at high altitude on the Qinghai-Tibet Plateau. By sequencing and comparing the genomes of five high altitude wolves from Tibet and Qinghai and four wolves from lowland populations in Inner Mongolia and Xinjiang, the researchers saw signs of selection in and around three wolf genes suspected of boosting oxygen delivery and heart function in high altitude, low oxygen living conditions. The same genes — EPAS1, ANGPT1, and RYR2 — are reportedly under selection in high altitude human populations as well, study authors noted, pointing to "similar evolutionary constraints on natural selection in wolves and humans of the Qinghai-Tibet Plateau."
Members of the Sequencing Initiative Suomi (SISu) project looked at loss-of-function variants in Finnish individuals for another PLOS Genetics paper. Using whole-exome sequences from 3,000 Finnish individuals and as many individuals from other European populations, researchers looked for variants found at frequencies of between 0.5 percent and 5 percent frequency in the Finns, a population stemming from a small founder population. As it turned out, members of the Finnish population appeared to have more low-frequency variants that are predicted to interfere with protein function than non-Finnish individuals, though their exomes contained fewer overall variants. In a cohort of almost 36,300 Finns, they saw also signs that such loss-of-function variants can affect individuals' phenotypes and disease risk patterns.
A PLOS One study by Memorial Sloan-Kettering Cancer Center researchers suggests that the process of breast cancer metastasis involves extensive reorganization of epigenetic marks in the tumors. The team did array-based methylation and expression profiling on matched primary breast tumor and metastasis samples from up to 44 women. The metastatic tumors tested displayed methylation — and related gene expression — shifts that varied depending on the breast cancer sub-type considered, the team reports, with many of these reorganizations involving methylation changes at relatively cytosine and guanine-poor regions of the genome.