Sexual selection can partly explain low frequencies of Segregation Distorter alleles

Keaney, Thomas A.; Jones, Ther�sa M.; Holman, Luke

Abstract

The Segregation Distorter (SD) allele found in Drosophila melanogaster distorts Mendelian inheritance in heterozygous males by causing developmental failure of non-SD spermatids, such that greater than 90% of the surviving sperm carry SD. This within-individual advantage should cause SD to fix, and yet SD is typically rare in wild populations. Here, we explore whether this paradox can be resolved by sexual selection, by testing if males carrying three different variants of SD suffer reduced pre- or post-copulatory reproductive success. We find that males carrying the SD allele are just as successful at securing matings as control males, but that one SD variant (SD-5) reduces sperm competitive ability and increases the likelihood of female remating. We then used these results to inform a theoretical model; we found that sexual selection could limit SD to natural frequencies when sperm competitive ability and female remating rate equalled the values observed for SD-5. However, sexual selection was unable to explain natural frequencies of the SD allele when the model was parameterized with the values found for two other SD variants, indicating that sexual selection alone is unlikely to explain the rarity of SD.

Citation

Keaney, T. A., Jones, T. M., & Holman, L. (2021). Sexual selection can partly explain low frequencies of Segregation Distorter alleles. Proceedings of the Royal Society B: Biological Sciences, 288(1959), https://doi.org/10.1098/rspb.2021.1190

• Journal Article Type: Article
• Acceptance Date: Sep 2, 2021
• Online Publication Date: Sep 29, 2021
• Publication Date: Sep 29, 2021
• Deposit Date: Oct 5, 2021
• Publicly Available Date: Oct 12, 2021
• Journal: Proceedings of the Royal Society B: Biological Sciences
• Print ISSN: 0962-8452
• Electronic ISSN: 1471-2954
• Publisher: Royal Society
• Peer Reviewed: Peer Reviewed
• Volume: 288
• Issue: 1959
• DOI: https://doi.org/10.1098/rspb.2021.1190
• Keywords: meiotic drive, gene drive, genomic conflict, sperm competition, mate choice
• Public URL: http://researchrepository.napier.ac.uk/Output/2808478