1. Rapid gene content turnover on the germline-restricted chromosome in songbirds
- Author
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Schlebusch, Stephen, Rídl, Jakub, Poignet, Manon, Ruiz-Ruano, Francisco, Reif, Jiri, Pačes, Jan, Albrecht, Tomas, Suh, Alexander, and Reifová, Radka
- Abstract
The germline-restricted chromosome (GRC) of songbirds represents an extraordinary and taxonomically widespread example of programmed DNA elimination. Despite its apparent indispensability in songbirds, we still know very little about the GRC’s genetic composition, function, and evolutionary significance. Here we assembled the GRC in two closely related species, the common and thrush nightingale. We identified 585 and 406 genes on the GRC of each species, respectively, many of them present in multiple copies. Interestingly, the GRC gene content differed dramatically between the two species, with only 192 genes being shared despite only 1.8 million years of species divergence. The chromosome appears to be under little selective pressure, with most GRC genes being present in pseudogenized fragments. Only one gene, cpeb1, had a complete coding region in all examined individuals of the two species and showed no copy number variation. The addition of this gene to the GRC corresponds with the earliest estimates of the GRC origin, making it a good candidate for the functional indispensability of the GRC in songbirds.
- Published
- 2022
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