The availability of hundreds of genomes allows us to learn rapidly about genomic differences between microorganisms. Comparative genomics shows that horizontal gene transfer, mutations and rearrangements are frequent events in most species. The molecular mechanisms for these events have been described in laboratory experiments and sometimes even under ‘natural conditions’. Beside, when put in different environments, a given bacterial genome shows drastic change in its profile of expression (as evidenced by transcriptomic or proteomic experiments). Thus, clearly genetic differences and variation in environmental conditions lead to phenotypic variability (i.e. as text books say genotype X environment = phenotype). However, there might be other sources of phenotypic variability as experiments show that even with a given genome in a given environment one observes phenotypic variability. Even if this was recognized already in the 50’s, the causes and consequences of this other source of phenotypic variability remain to be described presumably by developping new interdisciplinary tools.
['François Taddei']
Sources of genetic and phenotypic variability