Contrasting demographic histories of the neighboring bonobo and chimpanzee

Abstract

The Pleistocene epoch was a period of dramatic climate change that had profound impacts on the population sizes of many animal species. How these species were shaped by past events is often unclear, hindering our understanding of the population dynamics resulting in present day populations. We analyzed complete mitochondrial genomes representing all four recognized chimpanzee subspecies and the bonobo to infer the recent demographic history and used simulations to exclude a confounding effect of population structure. Our genus-wide Bayesian coalescent-based analysis revealed surprisingly dissimilar demographic histories of the chimpanzee subspecies and the bonobo, despite their overlapping habitat requirements. Whereas the central and eastern chimpanzee subspecies were inferred to have expanded tenfold between around 50,000 and 80,000 years ago and today, the population size of the neighboring bonobo remained constant. The changes in population size are likely linked to changes in habitat area due to climate oscillations during the late Pleistocene. Furthermore, the timing of population expansion for the rainforest-adapted chimpanzee is concurrent with the expansion of the savanna-adapted human, which could suggest a common response to changed climate conditions around 50,000-80,000 years ago.

Phylogeny of the jacchus group of Callithrix marmosets based on complete mitochondrial genomes

“…Another key application of mitochondrial genomics to marmoset evolution will be within the realm of population genomics and demography. This application is still fairly uncommon for non‐human primates, with the exception of studies such as that of Hvilsom, Carlsen, Heller, Jaffre, & Siegismun (). Increasing the sequenced length of the mtDNA genome will allow for a more accurate depiction of intraspecific genetic diversity of marmoset species, which still remains understudied.…”

Strong influence of palaeoclimate on the structure of modern African mammal communities

“…Molecular evidence suggests that shifts in forest vegetation during glacial and interglacial climate change strongly influenced African primates, including vicariance and dispersal in guenons [38,70] and gorillas [36], and demographic patterns in chimpanzees [80] and mandrills [81]. In addition, bioclimatic envelope models of African mammals and birds provide evidence for three major forest refugia in Central and West Africa [40], which would have represented the only viable habitats for most of Africa's primates during glacial periods.…”

Chimpanzee genomic diversity reveals ancient admixture with bonobos

“…Unraveling the demographic histories of our closest living relatives provides an opportunity for comparisons with our own history, and thus for studying processes that might have played a recurring role in hominid evolution. Due to a paucity of fossil records (1), our understanding of the demographic history of the Pan clade has primarily relied on population genetic data from mitochondrial genomes (2,3), nuclear fragments (4,5), and microsatellites (6,7). More recently, the analysis of whole-genome sequences from chimpanzees and bonobos hinted at a complex evolutionary history for the four taxonomically recognized chimpanzee subspecies (8).…”