Fecal metagenome of Rhinopithecus roxellana (including infant monkeys)

Allomaternal nursing behavior, which is widespread in primates, is vital for infant survival, especially for some species inhabiting high-altitude temperate forests, such as Rhinopithecus roxellana. We aim to uncover the mechanism underlying this phenomenon by comparing the fecal microbiomes of allonursed infants (ANIs) and non-allonursed infants (NANIs) of R. roxellana. We found more probiotics and more immune-related genes abundant in the ANIs cohort than in the NANIs cohort, which can promote Treg cells proliferation, leading to a higher level of immune tolerance to gut bacteria. It might lead to a more diverse gut microbiome in infants, allowing the infants to digest the crude fiber more efficiently, which helps them survive in their first winter. Our findings revealed the mechanism of allomaternal nursing behavior improvement of infant survivorship occurred via enrichment of the gut microbiome, which possibly provide a new insight into the mechanism of adaptive evolution for primates.