The Hologenome Theory

A hologenome is defined as the sum of genetic information from both the host and its microbiota. This recently proposed theory of evolution considers the holobiont (the organism and all of its associated symbiotic microbes) a unit of natural selection and is based on four well documented generalizations:

  1. All animals and plants establish symbiotic relationships with microorganisms.
  2. Symbiotic microorganisms are transmitted between generations.
  3. The association between host and symbiont affects the fitness of the holobiont.
  4. Under environmental stress, the symbiotic microbial community can change rapidly.

These points taken together suggest that the genetic wealth of diverse microbial symbionts can play an important role in both the adaptation and evolution of higher organisms.

Image: BODY MICROBES, by Bruno Vergauwen.