Division of Baic Sciences & HHMI Investigator
Fred Hutchinson Cancer Research Center
Title: Rapidly evolving tales of rapidly evolving histones
Abstract: Harmit Malik studies the causes and consequences of genetic conflicts that take place between different genomes (e.g., host-virus interactions) or between components of the same genome (e.g., chromosomal competition at centromeric regions). He is interested in understanding these "molecular arms races" and how they drive recurrent genetic innovation, from the perspective of both evolutionary biology and human disease. Based on the unexpected discovery of rapid evolution of centromeric proteins in plants and animals, he and his collaborators first proposed the ‘centromere-drive’ model, in which centromeric DNA element act as selfish genetic elements to exploit asymmetries in female meiosis (in which only one of four meiotic products is chosen) for their own transmission, even at great cost to host fitness. Several aspects of the original ‘centromere-drive’ have now been elegantly demonstrated by other labs, but the question of what drives rapid evolution of centromeric proteins remains unsolved. Using a gene-swap strategy in Drosophila, in which centromeric histones are reverted to an ancestral state, his lab has pioneered a novel strategy to study the causes and consequences of this rapid evolution in vivo. His lab has also shown evidence for dramatic turnover in centromeric proteins, with evolutionarily young genes becoming essential for centromeric function whereas evolutionary old, essential genes can be rendered dispensable. Finally, his lab has shown how unusual genetic conflicts during meiosis may provide a basis of postzygotic reproductive isolation between recently diverged species. More recently, his lab has focused on studies of a rapidly evolving class of histone variants found exclusively in placental mammals, which may play a role in parental antagonism.
Host: Peter Andolfatto
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