Charting the genomic landscape of hybridisation and genetic introgression across the Lake Malawi cichlid adaptive radiation.

Recent genome studies suggest that hybridisation and genetic exchange among closely related species is more common than previously thought. Consequently, a central question in the study of biodiversity is the effect of genetic exchange on the formation and maintenance of species diversity. With more than 800 closely related species, the Lake Malawi cichlid fish adaptive radiation provides an intriguing model to study the frequency and evolutionary role of interspecific genetic exchange. Malinsky et al. (2018) found strong evidence for extensive gene flow early on in the Malawi radiation and made some links to adaptation. However, due to limitations in sampling and statistical inference methods, we are still lacking a comprehensive picture of the abundance and evolutionary role of genetic exchange in Malawi cichlids and in most other organisms. In this project I will establish a genomic framework for the joint inference of species relationships and genetic exchange, applying it to a unique dataset of more than 2000 genomes from 276 Malawi cichlid species to gain unprecedented insight into the abundance of genetic exchange between different populations, species and genera. Furthermore, I will refine a statistical method I developed during my Master's to test whether selection has acted on exchanged genetic material. In summary, this project will yield widely applicable genomic tools and insight into the role of gene flow in one of the most intriguing vertebrate radiations.

Keywords:EVOLUTION, ADAPTATION, CICHLIDS

Disciplines:Computational evolutionary biology, comparative genomics and population genomics, Biology of adaptation, Molecular evolution, Speciation, Population, ecological and evolutionary genetics

Project type:Collaboration project