Harper Jon Alexander, Morrow Edward H
Evolution, Behaviour and Environment Group, School of Life Sciences, John Maynard Smith Building, University of Sussex, Brighton BN1 9QG, UK.
Department of Environmental and Life Sciences, Karlstad University, Karlstad 651 88, Sweden.
Proc Biol Sci. 2025 Jan;292(2039):20242629. doi: 10.1098/rspb.2024.2629. Epub 2025 Jan 22.
Recombination plays a key role in increasing the efficacy of selection. We investigate whether recombination can also play a role in resolving adaptive conflicts at loci coding for traits shared between the sexes. Errors during recombination events resulting in gene duplications may provide a long-term evolutionary advantage if those loci also experience sexually antagonistic (SA) selection since, after duplication, sex-specific expression profiles will be free to evolve, thereby reducing the load on population fitness and resolving the conflict. The potential advantage of gene duplication may be tempered by the short-term deleterious effects on gamete and zygote survival, which may be tolerable in a species with high reproductive output but not with low reproductive output. We used datasets of candidate SA loci from and humans to test these ideas. As in humans, sexually antagonistic alleles in flies with net positive effects across the two sexes occurred at higher frequencies than alleles with net negative effects. In flies, higher recombination rates were associated with more intense levels of sexual conflict and genes with paralogues occur in regions with higher recombination rates, indicating gene duplication events are associated with a history of SA selection. Genes experiencing higher levels of conflict also showed both a higher proportion with paralogues and higher numbers of paralogues. Together, our findings reveal multiple lines of evidence for a possible route towards the resolution of an adaptive conflict via gene duplication that is facilitated by higher recombination rates.
重组在提高选择效率方面起着关键作用。我们研究重组是否也能在解决两性共享性状编码位点的适应性冲突中发挥作用。如果那些位点也经历性拮抗（SA）选择，重组事件中导致基因重复的错误可能会提供长期的进化优势，因为在基因重复后，性别特异性表达谱将能够自由进化，从而减轻群体适应性的负担并解决冲突。基因重复的潜在优势可能会受到对配子和受精卵存活的短期有害影响的限制，这在高繁殖率的物种中可能是可以容忍的，但在低繁殖率的物种中则不然。我们使用了来自果蝇和人类的候选SA位点数据集来验证这些想法。与人类一样，在果蝇中，对两性具有净正向影响的性拮抗等位基因出现的频率高于具有净负向影响的等位基因。在果蝇中，较高的重组率与更强的性冲突水平相关，并且具有旁系同源物的基因出现在重组率较高的区域，这表明基因重复事件与SA选择的历史相关。经历更高冲突水平的基因也显示出更高比例的旁系同源物和更多数量的旁系同源物。总之，我们的研究结果揭示了多条证据，表明通过基因重复解决适应性冲突的可能途径，而较高的重组率促进了这一过程。
