Topic 19 - Coevolution and Microbiome

What is Coevolution

Coordinated evolutionary changes that occur in pairs of organisms, typically to maintain or to refine functional interactions between those pairs. Likely when different species have close ecological interactions with one another.

Different Types of Coevolution

1. Mutualisms

   • both organisms benefit

   • can be interspecific facilitation (one species benefits either directly or indirectly), mutualistic facilitation, or specific mate recognition system (coevolution between male signal and female perception)

2. Antagonisms

   • one organism benefits and one is at a disadvantage (like predator and prey)

What is the Red Queen Hypothesis?

A specific case of antagonistic coevolution. Traits in one evolve against competing traits in the other. Fitness landscapes change perpetually. Adaptive advantage continually eroded. Changes closely governed by the risk of extinction. Over time, the probability of extinction becomes constant.

What is the Microbiome?

It is involved in intricate coevolutionary relationships with trillions of symbiotic organisms. Communities of interacting populations of different species. Interactions between host and microbes are bidirectional. Microbes classically viewed as pathogens. Majority of interactions are symbiotic. Diversity is the number, abundance and distribution of distinct species. Diversity linked to disease.

What are the 2 modes of Transmission of the Microbiome?

1. Vertical

   • common in mammals

   • transmission from parents to offspring

   • provides the pioneer microbial community

2. Horizontal

   • common in reptiles and invertebrates

   • transmission from diet and environment

What are Good Microbes?

Good microbes can also influence behavior and development. 

What is the Memory of the gut Microbiome?

“Biological memory” – respond and adapt to changes. Accessibility and responsiveness to environmental exposures. Disruptions to microbial composition during development can be enduring. Pivotal in adaptive capability and ecological memory = microbiome resilience.

How is the Microbiome related to Evolution?

• Diet-specific microbiota influence mating preferences

• Mate choice plays a role in divergence and speciation

• Probiotic microbes

• Anxiety is heritable, and heritability is a part of natural selection

Inbreeding increases homozygosity. Gut microbiota are important for kin recognition. Social species share common microbes because of social interactions.

Challenging Conventional Ideas of Evolution

• Epigenetic

• Microbiome

• Phenotypic plasticity

• Adaptive landscapes

• Jumping genes

• Systems biology