|Date||24 May 2018|
|Time||16:00 - 17:00|
Rijksuniversiteit Groningen, Genomic basis of evolutionary adaptations & ecological interactions
To understand the intricate genetic networks that underlie variation in immunity, and to map how the genome changes during the evolution of immunity, we use Drosophila-parasitoid interactions as model system. The ability to survive parasitoid attack varies hugely both among and within species of the Drosophila genus, from absent to high resistance. Combining phenotypic assays, comparative genomics, population genomics and experimental evolution approaches, we identified genome changes associated with the gains, losses and increases of parasitoid resistance. Comparing 11 sequenced Drosophila species, we showed that the evolution of parasitoid resistance coincided with the acquiring of a novel type of differentiated hemocyte (i.e. insect blood cell) and with the duplication of 11 genes that are up-regulated during the immune response after parasitoid attack. We characterized the impact of a selective sweep for parasitoid resistance on the genome, using experimental evolution followed by genome sequencing. Several narrowly defined genomic regions showed strong signatures of selection and candidate genes were identified that potentially confer increased parasitoid resistance. Comparing 8 natural D. melanogaster populations, we find that physiological and genetic mechanisms underlying phenotypic variation differ substantially among populations. Combined, this emphasizes that short- and long-term evolutionary responses can result in markedly different genome changes.