Satellite DNA-mediated diversification of a sex-ratio meiotic drive gene family in Drosophila.

Christina A Muirhead, Daven C Presgraves

Nature ecology & evolution 2021 Dec

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Sex chromosomes are susceptible to the evolution of selfish meiotic drive elements that bias transmission and distort progeny sex ratios. Conflict between such sex-ratio drivers and the rest of the genome can trigger evolutionary arms races resulting in genetically suppressed 'cryptic' drive systems. The Winters cryptic sex-ratio drive system of Drosophila simulans comprises a driver, Distorter on the X (Dox) and an autosomal suppressor, Not much yang, a retroduplicate of Dox that suppresses via production of endogenous small interfering RNAs (esiRNAs). Here we report that over 22 Dox-like (Dxl) sequences originated, amplified and diversified over the ~250,000-year history of the three closely related species, D. simulans, D. mauritiana and D. sechellia. The Dxl sequences encode a rapidly evolving family of protamines. Dxl copy numbers amplified by ectopic exchange among euchromatic islands of satellite DNAs on the X chromosome and separately spawned four esiRNA-producing suppressors on the autosomes. Our results reveal the genomic consequences of evolutionary arms races and highlight complex interactions among different classes of selfish DNAs. © 2021. The Author(s), under exclusive licence to Springer Nature Limited.

Citation

Christina A Muirhead, Daven C Presgraves. Satellite DNA-mediated diversification of a sex-ratio meiotic drive gene family in Drosophila. Nature ecology & evolution. 2021 Dec;5(12):1604-1612