A holobiont is an assemblage of a host and the many other species living in or around it, which together form a discrete ecological unit. The components of a holobiont are individual species or bionts, while the combined genome of all bionts is the hologenome. The concept of the holobiont was initially defined by Dr. 📝Lynn Margulis in her 1991 book Symbiosis as a Source of Evolutionary Innovation,[1] though the concept has subsequently evolved since the original definition.[2]

Holobionts include the host, virome, microbiome, and other members, all of which contribute in some way to the function of the whole.[3][4] Well-studied holobionts include reef-building corals and humans.[5][6] However, there is controversy over whether holobionts can be viewed as single evolutionary units.

A holobiont is an organism composed of communities of organisms, themselves holobionts that are composed of other communities of organisms.

Reflections

“The bicycle is a curious vehicle. Its passenger is its engine. ” ~ John Howard