Social Microbiome (Reena Debray)

Our gut microbiomes have co-evolved and diversified alongside us throughout our evolutionary history. They expand the range of foods we can digest and train our immune system to recognize pathogens. In the Social Microbiome Group, we use behavioral and molecular methods to study the gut microbiomes of our close primate relatives and understand the evolution of our lineage.

Cultivating unknown species from wild microbiomes: Microbial sequence databases tend to be biased towards commonly studied host species such as humans. In baboons, for example, it is typical for only 10-20% of sequencing reads to match any entries in public databases, and for the rest to remain uncharacterized. We are culturing and sequencing bacteria collected from wild primate populations, along with assembling novel genomes from metagenomes, to expand species- and strain-profiling databases for our non-model systems.

Microbiome evolution within hosts: Microbiomes are a fascinating system for studying evolution within complex ecological communities due to their rapid evolutionary potential, genetic tractability, and interactions with their hosts. In theory, a moderately-sized bacterial population in the gut can experience every possible point mutation across the genome every generation. Yet whether populations actually do respond to selection as rapidly as suggested by their mutational supply, or whether/how they are constrained by forces such as clonal interference or other community members, remain largely unknown. We work with long-term gut microbiome datasets from a wild baboon population to learn about the tempo, mode, and targets of natural selection in microbial communities.

Social effects on animal microbiomes: The structures of animal social systems are thought to be shaped by the various evolutionary costs and benefits of living with others – for example, improved foraging efficiency or increased susceptibility to disease. Recent research suggests another possible benefit: that social animals acquire some of their microbiome from their conspecifics. If this is true, then social partners may act as reservoirs of beneficial microbes for individuals with newly developing or recently disrupted microbiomes. We aim to understand how social living influences animal microbiomes, and in turn how microbes have shaped the costs and benefits of social evolution.