ReversePlasticity · Evolution of the thermal plasticity of gene expression: a reverse evolution experiment using Drosophila simulans.

Evolution of the thermal plasticity of gene expression: a reverse evolution experiment using Drosophila simulans.

Phenotypic plasticity, the ability of a genotype to express distinct phenotypes in different environments, is assumed to facilitate individuals coping with new or rapidly changing environments. In the context of climate change, the phenotypic response to temperature has received particular attention since thermal plasticity is affecting the survival of populations and species distribution. Although temperature is an important variable that affects many traits, the genetic basis of phenotypic plasticity evolution remains poorly explored. Temperature does not only affect integrated components of phenotype such as physiology or behaviour but also gene expression. Indeed, the concept of phenotypic plasticity was originally conceived for phenotypes but it can be also applied to patterns of gene expression or protein profiles. Understanding how adaptive plasticity is evolving in populations exposed to new environments could provide insights into the mechanisms driving gene expression temperature sensitivity as well as its molecular basis. Experimental evolution is a highly promising approach to study adaptation, as this research tool controls for the environment and the population history and allows for replication. An innovative way of characterizing the evolution of adaptive plasticity is to monitor gene expression patterns after evolution in stressful or novel environments during experimental evolution studies. The pattern of gene expression change across a range of environments can be defined as the reaction norm of the molecular phenotype of these populations. With the development of Next Generation Sequencing (NGS), it is now possible to identify changes in gene expression and the associated reaction norms during evolution. The objectives of our project were to study the interplay between phenotypic plasticity and genetic evolution during adaptation to novel thermal environments: - Is phenotypic plasticity in natural population adaptive? - Does adaptive phenotypic plasticity prevent genetic evolution? Facilitates it? - Can we identify genomic regions rapidly evolving in response to temperature changes and how these changes affect phenotypic plasticity? Our research demonstrated that the evolution of phenotypic plasticity is involved during adaptation to novel thermal environment. We showed that natural populations exhibit genetic variation for plasticity that can rapidly evolve in laboratory experiments. We then identified the genetic regions associated with these phenotypic changes and described their evolution. Because these genes also show pronounced clinal variations in natural populations, we conclude that similar processes drive rapid temperature adaptation in the wild.

Data: CORDIS, © European Union