MAPGenome · Mapping migration and adaptation in genomes

Mapping migration and adaptation in genomes

Understanding the interplay of adaptation and migration at the genomic level is a fundamental goal of evolutionary biology, with wide applications in situations where these two forces operate, e.g. pesticide resistance or species invasion. These processes underlie emergent societal concerns, reflected in EU policies priorities, in agriculture, global change biology, and human health. Yet, this goal remains largely elusive, mainly because genetic signatures of local adaptation are confounded by other evolutionary processes, such as past demography, the removal of deleterious mutations and recombination rate variation. We moved towards achieving this goal by combining theoretical results and development of bioinformatics methods, with experimental evolution and genome-wide data from both experimental and natural populations. We focused on a major crop pest, the spider mite Tetranychus urticae, with a haplo-diploid mode of reproduction. Our modeling results predict that divergent selection is more efficient in haplo-diploids than diploids in scenarios with gene flow. As a result, such species can diverge even with migration. To test these predictions, we are using experimental evolution, following spider mite populations adapting to a new environment under controlled conditions, with and without migration. We are quantifying changes through time in life-history traits and genomic patterns. Preliminary results indicate a slower rate of adaptation in treatments with migration. Moreover, we are finishing the development of a bioinformatics method to map variation in gene flow across the genome, which can be used by other researchers. Finally, to study the impact of gene flow we analyzed genomic data from natural populations from different systems (fish to primates). Results support that genetic signatures of past gene flow are widespread across systems. In sum, we contributed to move the field towards a comprehensive characterization of the genomics of adaptation in face of gene flow. The theory, methods and data resulting from this MSCA will be of general application to address fundamental questions on speciation and ecology, while providing a transferable framework to tackle societal challenges, from agriculture to global change.

Data: CORDIS, © European Union