Genome-wide signatures of selection and convergent evolution in corvids

• Applicant: Dr. Verena Esther Kutschera
• Subject Area: Evolution, Anthropology
• Term: from 2015 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 282481844

Organisms have the ability to adapt to changing environmental conditions. Adaptive genetic variation beneficial to its carrier will be promoted in the population through positive selection, whereas negative selection guarantees stability of central housekeeping functionality. However, owing to a historical lack of genome-wide data, our knowledge about how selection shapes the genome and if e.g. the effect of a new mutation is deleterious, neutral or advantageous, is limited.The technological advances of the past years provide us now with the opportunity to investigate the effects of selection pressure on different parts of the genome; in humans ultimately a question of high medical relevance. For the first time sufficient data can be generated to test fundamental predictions of evolutionary theory. A combined approach of interspecific comparative methods, integrating over millions of years, with intraspecific population genomic analyses, reflecting evolutionary processes over several thousand generations, holds particular promise. If consequently applied in a group of organisms sharing similar life histories, such a combined approach further has the potential to reveal hotspots of selection in the genome, entering the fascinating theme of convergent evolution.Birds are a well suited model system to address these questions: their genomes are highly conserved and poor in repetitive elements, and their karyotypic organization into micro- (<20 mega base pairs [Mb]) and macrochromosomes (>40 Mb) provides naturally high variance in recombination rates. Aim of this project is to employ a combination of comparative and population genomic approaches in the bird genus Corvus, spanning about 15 million years of evolution. This proposal rests on the availability of genome assemblies from 12 crow and raven species and population genomic re-sequencing data for a subset of nine, to be extended during the course of the project. In multiple steps this data will be used to 1) infer the genomic landscape of selection (strength and direction of selection coefficients), 2) assess the impact of structural genetic variation (recombination) on selection, 3) investigate the importance of sex chromosomes during speciation (fast-Z effect) and 4) finally assess the prevalence of molecular convergence that in parts may tentatively be linked to a recurring pied color phenotype in some species against a background of otherwise all-black species. This project is expected to contribute significantly to our understanding of adaptation, convergent evolution and their interplay with species divergence.

• DFG Programme: Research Fellowships
• International Connection: Sweden
• Host: Professor Dr. Jochen B. W. Wolf