2026-02-04 国立遺伝学研究所
本研究で提案する仮説の概要。この仮説は祖先種の中に表現型は似ているが遺伝的に分化した2系統が存在する状況(a)を想定する。これらの系統間の雑種集団ではメスの選好性の個体間バリエーションが増加し、性選択の作用が変化する(b)。その結果、新たな求愛ディスプレイを持つ新種の形成が促進される(c)。
<関連情報>
- https://www.nig.ac.jp/nig/ja/2026/02/research-highlights_ja/rh20260105.html
- https://royalsocietypublishing.org/rspb/article/293/2064/20252605/479923/The-interplay-of-sexual-selection-and
性選択と交雑の相互作用は性的放散を促進する可能性がある The interplay of sexual selection and hybridization can drive sexual radiation
Kotaro Kagawa
Proceedings of the Royal Society B Published:04 Feb 2026
DOI:https://doi.org/10.1098/rspb.2025.2605
Abstract
Many evolutionary radiations involve diversification of exaggerated sexual displays, but little is known about how they are formed. It has been theorized that there can be multiple stable equilibria in the evolution of sexually selected traits, by which multiple species having distinct sexual displays and mate preferences can stably persist. However, these theories alone do not fully explain the speciation process because the stability of each equilibrium will impede the formation of a new species from an existing species that is already occupying one of the stable equilibria. To explain the evolutionary process that forms species with diverse sexual displays, we here propose that hybridization between phenotypically similar but genetically divergent lineages can catalyse speciation by sexual selection, via the creation of genotypic and phenotypic variation. Using evolutionary simulations, we show that hybridization giving rise to variation in mate preference and sexual displays can alter the sexual selection regime, thereby creating opportunities for evolutionary shifts towards previously unoccupied stable equilibria. Thus, hybridization can facilitate evolutionary exploration of the stable evolutionary equilibria that sexual selection generates, leading to speciation accompanied by the diversification of exaggerated sexual displays.
