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.

Microbes Can Influence Evolution of Their Hosts

July 18, 2013 — You are not just yourself. You are also the thousands of microbes that you carry. In fact, they represent an invisible majority that may be more you than you realize.

These microscopic fellow travelers are collectively called the microbiome. Realization that every species of plant and animal is accompanied by a distinctive microbiome is old news. But evidence of the impact that these microbes have on their hosts continues to grow rapidly in areas ranging from brain development to digestion to defense against infection to producing bodily odors.

 Continue Reading