Concordant Evidence for Positive Selection on Genes Related to Self-Domestication in Bonobos and Early Humans

The domestication syndrome refers to a suite of traits characteristic of domesticated animals, including neotenic aspects of morphology and behavior, increased docility, and reduced reactive aggression. The term self-domestication refers to a process governed by social selection against reactive aggression within species, with effects parallel to those of selection for tameness. There are several recent hypotheses concerning the mechanisms of human self-domestication. It has also recently been hypothesized that bonobos have undergone a process of self-domestication after diverging from their common ancestor with chimpanzees. Here we investigate independent patterns of selection on bonobos (relative to chimpanzees) and humans (relative to Neanderthals) in genes associated with domestication in previous research. We used the Great Apes selection browser and the Neanderthal-human selection browser (in the UCSC Genome Browser) to compare concordant patterns of selection (at the level of gene region and peak selection regions), in a set of 9 genes, to 50 genes found to be under positive selection in bonobos in a prior survey. In terms of concordance, we found that the vasopressin receptor, avpr1b, was ranked first in the peak region and second in the gene region, the oxytocin receptor, oxtr, was ranked second in peak region and sixth in gene region, the serotonin receptor, htr1f, was ranked third in gene region, and the gtf2i gene was found to be ranked ninth for peak region. We argue that our results provide preliminary molecular evolutionary support for parallel patterns of positive selection on genes associated with self-domestication in bonobos and humans. Public Significance StatementPrevious research suggests that both bonobos and humans have undergone selection for increased cooperation in the context of self-domestication. Research presented here compares signals of selection on genes associated with sociality and cooperation in bonobos (relative to chimpanzees) and humans (compared with Neanderthals). The results support the prediction (from the self-domestication hypothesis) that selection has affected these genes in both bonobos and humans, independently in parallel.