Final Report Summary - FUNCSPECGEN (What is the engine of biodiversity? Comparative and Functional Speciation Genetics in the Post-genomic Era)
The evolution of genetic barriers opposing interspecific gene flow is key to the origin of new species. To address this question empirically we chose to focus on an evolutionary young, avian model system where the evolutionary processes contributing to population divergence can be 'caught in the act'. All-black carrion crows (Corvus (corone) corone) and grey-coated hooded crows (C. (c.) cornix) meet in a stable and narrow contact zone that likely formed in the Early Holocene. Assortative mating and social marginalization of minority phenotypes based on plumage pigmentation patterns act in concert to reduce the amount of crossbreeding. Combining fieldwork and behavioural assays with a multitude of (functional) genomic approaches and mathematical modelling we deciphered the interplay between phenotypic divergence and selection at the molecular level. In brief, this project revealed that few, large-effect loci coding for plumage colouration govern prezygotic isolation under conditions of gene flow. Expanding the framework to other species within the genus Corvus and beyond more generally revealed the evolutionary processes shaping genetic biodiversity within and between species.