" Phylogenomic insights into adaptive radiations "
Adaptive radiations are iconic examples of explosive diversification, such as that displayed by Darwin's finches on the Galapagos Islands or Anolis lizards in the Caribbean. The processes that lead to rapid phenotypic divergence during such radiations have captured evolutionary biologists for many decades. Recently, the generation of large genomic datasets for adaptively radiating groups, coupled with methodological innovations for phylogenetic analyses at unprecedented scales, have allowed novel insights into this fascinating process. Here, I will present the insights gained from phylogenomic analyses for two of the world's most species-rich adaptive radiations – that of cichlid fishes in the East African Lake Tanganyika with around 250 species, and that of notothenioid fishes in Antarctic waters with about 110 species. Our analyses conclusively resolve the relationships among subgroups and reveal a comparable age of both radiations. For Lake Tanganyika cichlids, we further identify pervasive signals of introgression – past genetic exchange between species – indicating that there was and is wide-ranging hybridization among lineages. I show that this introgression has increased genetic diversity in the affected species, and present a model according to which this could lead to self-perpetuating diversification, that could potentially explain why species accumulation is so much more explosive in adaptive radiations, compared to other groups on the tree of life.
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Michael Matschiner is Associate Professor in Vertebrate Zoology at the University of Oslo, with an interest in species diversification. After a short stint at UNIL, he gained his PhD in Evolutionary Biology at the University of Basel, followed by postdoctoral research in New Zealand and Norway, and again in Switzerland at the universities of Basel and Zurich. He returned to Norway a second time in 2021 to accept his current position. His research uses genomic and bioinformatic tools to investigate the processes generating biodiversity, with a focus on vertebrates.
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