Speciation Genomics in Natural Populations

The view of species as entities amenable to evolutionary change elaborated by Charles Darwin laid the conceptual foundation for our current understanding of how biodiversity can be generated. Initially marred by a rudimental understanding of hereditary principles, evolutionists gained appreciation of the mechanistic underpinnings of adaptation and speciation following the merger of Mendelian genetic principles with Darwinian evolution. By the late 20th century a mature framework in theoretical and empirical evolutionary genetic research had been developed to investigate the genetic basis of species diversification. Spurred by a recent revolution in nano-sequencing technology speciation genetic research has become increasingly open to genetic non-model organisms. Genome-wide processes can now be investigated at unprecedented resolution in essentially any eco-evolutionary model species of interest. This development has expanded speciation research beyond the traditional boundaries and unveils the genetic basis of speciation from manifold perspectives and at various stages of the splitting process. In this talk I will give an overview on recent work in the growing field of ‘speciation genomics’ unraveling the genetic underpinnings of adaptation and speciation from a micro-evolutionary perspective. While providing examples from a variety of taxa, I will capitalize on own recent work in the Eurasian crow species complex. This system is characterized by parallel evolution of a sexually selected plumage phenotype and lends itself to studying population differentiation across the speciation continuum at different time points in the evolutionary trajectory. Population genomic analyses of >100 re-sequenced genomes from across the species’ range combined with transcriptome data and other functional assays provide first insight into processes underlying the built-up of genomic differentiation and its relationships to reproductive isolation.