Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA.
Sci Adv. 2024 Jan 5;10(1):eadj6958. doi: 10.1126/sciadv.adj6958. Epub 2024 Jan 3.
Because human same-sex sexual behavior (SSB) is heritable and leads to fewer offspring, how SSB-associated alleles have persisted and whether they will remain in human populations are of interest. Using the UK Biobank, we address these questions separately for bisexual behavior (BSB) and exclusive SSB (eSSB) after confirming their genetic distinction. We discover that male BSB is genetically positively correlated with the number of offspring. This unexpected phenomenon is attributable to the horizontal pleiotropy of male risk-taking behavior-associated alleles because male risk-taking behavior is genetically positively correlated with both BSB and the number of offspring and because genetically controlling male risk-taking behavior abolishes the genetic correlation between male BSB and the number of offspring. By contrast, eSSB is genetically negatively correlated with the number of offspring. Our results suggest that male BSB-associated alleles are likely reproductively advantageous, which may explain their past persistence and predict their future maintenance, and that eSSB-associated alleles are likely being selected against at present.
由于人类同性性行为（SSB）是可遗传的，并导致后代较少，因此 SSB 相关等位基因是如何持续存在的，以及它们是否会在人类群体中存在，这是人们感兴趣的问题。我们在确认双性恋行为（BSB）和排他性 SSB（eSSB）的遗传差异后，分别使用英国生物库来解决这些问题。我们发现，男性 BSB 与后代数量在遗传上呈正相关。这种出乎意料的现象归因于男性冒险行为相关等位基因的水平多效性，因为男性冒险行为与 BSB 和后代数量在遗传上呈正相关，并且控制男性冒险行为的遗传可以消除男性 BSB 与后代数量之间的遗传相关性。相比之下，eSSB 与后代数量在遗传上呈负相关。我们的研究结果表明，男性 BSB 相关等位基因可能具有生殖优势，这可能解释了它们过去的持续存在，并预测了它们未来的维持，而 eSSB 相关等位基因目前可能正在被选择淘汰。
