Melissa Barbara Manus

The human microbiome — the collection of microorganisms (and their genes) that live in, on, and around us — represents an interface through which contact with the environment impacts human biology. More specifically, contact with the social environment shapes host microbial communities, which in turn influence host physiology and immune system development. Despite these important connections, we have only a basic understanding of how the microbiome is first established. While infants acquire microbes through physical contact with mothers, it is unclear how social interactions with other caregivers influence microbial development. Unlike other great apes, human mothers rely on other caregivers, or alloparents, for substantial infant care, suggesting an additional route for sharing microbes with infants. Because behaviors like holding and carrying promote frequent skin-to-skin contact between infants and alloparents, the infant skin microbiome is likely affected by these social interactions. Thus, this project investigates how variation in early life social environments, including allocare, influences the infant skin microbiome. By coupling microbiome data with surveys on sociocultural factors related to infant social environments, this study has the potential to offer a novel perspective on the benefits of allocare to infants, as well as inform studies on early life microbial exposures and health outcomes.