Should Evolution Treat Our Microbes as Part of Us?

Hologenomes contain vastly more genes than the host genome alone, and since at least a fraction of the microbial genes have significant bearing on the survival and reproduction of the host, we need to consider the hologenome as a possible unit of selection if we want to understand the evolution of the holobiont. For such holobionts, Bordenstein says, you can’t understand the evolution of either the host genome or the microbial genomes in isolation because the community of organisms as a whole shapes the traits of the individual. Proponents of this hologenomic concept of evolution argue that if there is a fidelity across generations between hosts and microbes, then the holobiont embodies a coming together of numerous, disparate evolutionary lineages into a singular being, a coalition of many that contributes to the functional integrity of the whole.

Source: www.quantamagazine.org