Research Seminar: Dr. Daniel MacQueen - University of Edinburgh
Dr. Daniel Macqueen hosted by Dr. Tom Williams
Life Sciences Seminar Room G13/G14
Genome duplication & diversification: insights served with salmon.
The duplication and subsequent divergence of genetic material is a key mechanism of evolution. When the genetic blueprint is doubled by whole genome duplication, which is common in eukaryotes, assuming the affected lineage survives an initial wake of genetic challenges, a new horizon of genetic possibilities awaits. Positive associations between genome duplication and evolutionary diversification have been proposed under many definitions and models. However, debate surrounds such ideas and there seem to be no ‘catch all’ rules across taxa. The expansion of new genomic resources provides us with increasing power to address such issues, in doing so better understanding fundamental evolutionary processes.
My lab primarily studies salmonid fishes - whose common ancestor underwent genome duplication 95 MY ago - in fundamental and applied research that integrates genomics, evolution and physiology. Commercial and scientific interest in this fish group has driven major advances in genomic resources, and for the first time we now have high-quality genome sequences for many key species. I aim to demonstrate that salmon and its relatives offer a beautiful model for linking genome duplication with evolutionary and functional diversification. I will focus on the outcomes of ‘rediploidization’, where duplicated chromosome sets revert back to diploid pairing, potentially over millions of years. Similar processes happen after all genome duplication events and are key to evolutionary and functional outcomes. Perhaps most significantly, duplicated genes created by genome duplication will only diverge in sequence and function after this process is resolved.
My seminar will highlight my lab’s comparative and phylogenomic studies of salmonids that improve our understanding of the rediploidization process and its impacts on genetic and functional diversification. I will show that genome duplication events need not be followed by an explosion of novel genetic and functional diversity, but instead, owing to the delayed nature of rediploidization in large regions of the genome, can have gradual impacts that play out over tens of millions of years, with great potential for lineage-specific outcomes. Moreover, delayed rediploidization may be mirrored at higher scales influencing phylogenetic patterns, potentially explaining the observation of ‘time-lags’ between genome duplication and diversification. Finally, I will argue that processes of genome evolution highly evident in salmonid genomes are more widespread than appreciated, and influential to large-scale diversity in many eukaryotes.
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