Notable: Gorilla genomes illuminate phylogeography

Notable paper: Kimberly F. McManus, Joanna L. Kelley, Shiya Song, et al. 2015. Inference of Gorilla demographic and selective history from whole genome sequence data. Molecular Biology and Evolution (early online) doi:10.1093/molbev/msu394

Synopsis: McManus and colleagues sequenced 17 gorilla genomes to medium coverage, mostly western lowland gorillas with 2 eastern lowland and 1 Cross River gorilla. They find that these populations diverged relatively recently in the Pleistocene, with the Cross River population dividing from western gorillas around 50-70 thousand years ago, and the western and eastern gorillas separating around 250,000 years ago. This result is basically consistent with other recent work showing that gorilla populations became regionally distinct in the later Pleistocene.

Bottom line: I’ve long thought that gorilla population structure was an interesting model to compare to Pleistocene humans. Early genetic sequencing, mainly of mtDNA, led many people to think that eastern and western gorillas were distinct well before 1 million years ago. In part, the greater genetic variation of gorillas complicated early attempts to understand their population history, and sequencing of whole genomes has vastly increased the statistical power to test hypotheses about ancient gorillas. Today’s perspective shows that the largest differences between gorilla populations emerged on a shorter timeline than the differences between Neandertals, Denisovans and their African contemporaries.