Research

Context and Issues
Adaptation of organisms to contrasting environmental conditions is a major driver of species diversification. However, we know very little on the genetic basis underlying ecologically-relevant traits, and on how and at what speed adaptive divergence leads to genetic differentiation. Here, we will use the pea aphid, a well-suited system for adaptive genomics, which conveniently shows a complex of plant-specialized biotypes, ranging from sympatric host races to incipient species, and resulting from a recent adaptive radiation

Objectives

The repeated shifts to new host plants in the pea aphid complex offer a unique opportunity to test parallel adaptation, i.e. the process by which adaptation to different plants would involve the same genes or the sharing of metabolic pathways. The Mecadapt project aims at 1) reconstruct the evolutionary history of plant specialization and biotype formation, 2) identify genomic regions under divergent selection and characterize the genomic architecture underlying plant-based differentiation, and 3) identify genes and functions involved in plant specialization in the pea aphid complex.

Methodology

This project will combine novel phylogenetic and population genetic analyses of massive genomic dataset obtained on aphid populations collected throughout the world on different legume plants to test whether biotypes across the distribution range of the pea aphid have a single origin and diversified in sympatry, and to pinpoint genomic regions involved in plant specialization. Crosses between biotypes will be performed and F2 hybrids will be phenotyped and genotyped to identify QTLs linked with plant adaptation. Innovative tools will be used to characterize the function of candidate genes identified in the genome scan and QTL analyses.

Collaborations

• INRAE CBGP, Montpellier : Emmanuelle Jousselin, Renaud Vitalis, Mathieu Gautier
• CNRS ISEM, Montpellier : Carole Smadja
• University of Sheffield, UK: Roger Butlin
• Maynooth University, Ireland: James Carolan

 Funding and Support: ANR