Séminaire Ecobio - Hugo Dore (IUEM Brest)

How is genetic diversity distributed within bacterial species?
The methods routinely used to study the composition of microbial communities allow for a description of species abundance, but are blind to the diversity existing within each species. Yet, bacteria from a given species can possess different genotypes, i.e. different alleles of their genes or different allele combinations. Under the effect of evolutionary forces (selection, drift) and migrations, the alleles present in a population can vary in frequency or disappear over time.
I study this question of the distribution of intraspecific diversity using environmental metagenomics. I am focusing more particularly on coastal environments, and will present the results from two studies. The first one explores the genetic structure of bacterial populations in benthic biofilms found in a naturally fragmented habitat. The second study focuses on temporal variations in populations of planktonic bacteria in the bay of Brest, through the analysis of an unprecedented 8-year time series. In both cases, the results reveal very contrasted dynamics between species