The dietary adaptation of animals is a powerful driving force for species niche differentiation and speciation, and the genetic mechanisms underlying adaptive evolution have been a research hotspot. Among primates, although there are many species that feed on high-fiber foods such as leaves, only the colobine primates (Colobinae), similar to herbivorous ruminants, have evolved a pattern of foregut fermentation. The evolutionary strategy of phenotypic convergence between the two clades provides an opportunity to explore the genetic mechanism of folivorous or herbivorous diet adaptation in mammals. We explored the molecular convergence of colobine primates and ruminants in the host genomes and host-associated microbiomes. Analysis of host genomic convergence revealed several convergent amino acid substitution sites, including PLA2G4E and PLA2G4F related to lipid metabolism, RPP25 as a component of ribonucleases, and TACR2 involved in positive regulation of gastric smooth muscle differentiation and contraction. Additionally, based on the genome-wide functional convergence test, genes under positive selection and rapidly evolving genes in both groups were significantly enriched in immune action, microbial regulation, energy metabolism, epithelial development, and other pathways. Analysis of 16S data showed high similarity between foregut samples of colobines and ruminants, while this phenomenon was not observed in hindgut samples. We also identified six highly expressed bacterial genera in both colobines and ruminants associated with cellulose and lignin degradation. These findings contribute to our understanding of the genetic basis of foregut fermentation in primate evolution and shed light on theories concerning adaptation to the environment and dietary transitions during primate radiation.
Study based on molecular convergence offer insight into adaptation to folivorous diet in primate subfamily Colobinae