Yamazaki Haruka, Mori Seiichi, Kishida Osamu, Nagano Atsushi J, Kokita Tomoyuki
Faculty of Agriculture Kyushu University Fukuoka Japan.
The Institute of Regional Development Gifu Kyoritsu University Ogaki Japan.
Ecol Evol. 2025 Jan 9;15(1):e70795. doi: 10.1002/ece3.70795. eCollection 2025 Jan.
Territorial aggression is widespread across the animal kingdom and is expressed in diverse ecological and social contexts. In addition, there are marked variations in the degree of male reproductive territoriality within and between species. These differences are often attributed to genetic components. However, the evolutionary genetic mechanisms in wild animals are poorly understood. This study explored the genetic basis of divergent male territorial aggressiveness between two Japanese freshwater populations, Gifu (GF) and Tomakomai (TM), in the threespine stickleback, which is a well-known model system for both behavioral ecology and evolutionary genetics. First, our field survey indicated that the distribution of reproductive territories differed greatly across breeding habitats between the focal populations, and the density of reproductive territories was much greater in the GF population. Second, a one-on-one arena aquarium experiment on male-male combat using wild-caught and common-garden-reared males revealed that GF males were genetically more aggressive than TM males. Finally, we performed quantitative trait loci (QTL) analysis using an F hybrid cross between the two populations to identify the causal genomic regions contributing to the divergence in male territorial aggressiveness. Our QTL analysis identified a single significant locus in an aggression-related behavioral component, that is, the number of bites of focal F males toward a GF stimulus intruder. Two notable behavior-related genes, and , are found near this locus. These genes have often been suggested to influence of aggressive behavior in animals; therefore, they are regarded as important candidate genes for further functional analyses. Thus, we are the first to provide a QTL-based genetic basis for population divergence in male territorial aggressiveness in the threespine stickleback.
领域性攻击行为在动物界广泛存在，并在多样的生态和社会环境中表现出来。此外，物种内部和物种之间雄性生殖领域性的程度存在显著差异。这些差异通常归因于遗传成分。然而，野生动物的进化遗传机制却鲜为人知。本研究探索了日本淡水三刺鱼两个种群岐阜（GF）和苫小牧（TM）之间雄性领域攻击性差异的遗传基础，三刺鱼是行为生态学和进化遗传学领域著名的模式系统。首先，我们的实地调查表明，重点种群之间繁殖栖息地的生殖领域分布差异很大，且GF种群的生殖领域密度要大得多。其次，一项使用野生捕获和共同饲养的雄性进行的一对一竞技场水族箱雄雄争斗实验表明，GF雄性在基因上比TM雄性更具攻击性。最后，我们利用两个种群之间的F杂种杂交进行数量性状基因座（QTL）分析，以确定导致雄性领域攻击性差异的因果基因组区域。我们的QTL分析在一种与攻击相关的行为成分中确定了一个显著位点，即重点F雄性对GF刺激入侵者的咬击次数。在该位点附近发现了两个与行为相关的重要基因。这些基因常被认为会影响动物的攻击行为；因此，它们被视为进一步功能分析的重要候选基因。因此，我们首次为三刺鱼雄性领域攻击性的种群差异提供了基于QTL的遗传基础。
