Suppression of sex-ratio drive in Drosophila subobscura

Lyth, S, Gill, T, Manser, A, Tanianis, J, Hurst, GDD ORCID: 0000-0002-7163-7784, Betancourt, AJ ORCID: 0000-0001-9351-1413, Price, TAR and Verspoor, RL ORCID: 0000-0002-4328-7721 (2025) Suppression of sex-ratio drive in Drosophila subobscura Evolution, 79 (11). pp. 2394-2405. ISSN 0014-3820, 1558-5646

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Abstract

Selfish genetic elements enjoy an evolutionary advantage by enhancing their own transmission to offspring, and their genetic suppressors are favored when they re-establish fair inheritance patterns. Here, we study an X-linked sex ratio drive system (SR) in Drosophila subobscura, which kills Y-bearing sperm of SR males, resulting in the over-transmission of the SR chromosome and a strong female bias in their offspring. We surveyed D. subobscura populations in North Africa, which naturally harbor SR, and found that suppression occurs in ∼13.5% of wild-derived lines. We characterize this suppression phenotype through a series of crossing experiments, including multigenerational introgression of SR chromosomes into a suppressing genetic background. We show that introgression can restore normal offspring sex ratios or, in some cases, result in an excess of male offspring. This suppression appears to be a multilocus trait, involving autosomes and the Y chromosomes. Suppression of SR fails to ameliorate all costs of drive, with fully suppressed SR-carrying males having depressed fertility and low offspring egg hatch rates. Further examination of internal male reproductive organs using microscopy suggests that suppressed SR males also have abnormal testes. These factors may explain why the suppression fails to reach high frequencies, despite the strong advantage of suppressing SR.

Item Type:	Article
Uncontrolled Keywords:	Y Chromosome, Animals, Drosophila, Sex Ratio, Female, Male
Divisions:	Faculty of Health & Life Sciences Faculty of Health & Life Sciences > Inst. Infection, Vet & Ecological Sciences
Depositing User:	Symplectic Admin
Date Deposited:	05 Aug 2025 07:41
Last Modified:	24 Jan 2026 05:25
DOI:	10.1093/evolut/qpaf153
Open Access URL:	https://doi.org/10.1093/evolut/qpaf153
Related Websites:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3193915
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