GELIFES Seminars - Alexander Suh

Alexander Suh (Uppsala University)

Genome evolution in birds - A tale of two rather odd chromosomes

Genomes can differ between sexes of a species and even between tissues of an individual. For nearly a decade, short-read sequencing has allowed researchers to finally study genome evolution in a wide range of non-model organisms, however, many genomic regions remained difficult to study due to their extremely high epetitiveness. This was particularly the case for non-recombining regions of the genome such as the sex-specific Y or W chromosomes, as well as germline-restricted chromosomes. Using birds as an example, I will showcase how the recent emergence of single-molecule sequencing is currently further transforming the field of genome evolution. Avian female-specific W chromosomes appear to be poor in genes, highly enriched in transposable elements and endogenous retroviruses, and have undergone massive structural changes across bird evolution. Conversely, avian germline-restricted chromosomes appear to be rich in genes with high copy numbers and expression during embryo or gonad development, and are likely widespread across birds. Comparative genomics of W chromosomes and germline-restricted chromosomes across birds will help clarify the evolutionary significance of some of the last remaining uncharted territories of the genome.