Developmental Biochemistry, Biocenter, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany; The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA.
Biochemistry and Cell Biology, Biocenter, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany.
Curr Biol. 2021 Mar 8;31(5):911-922.e4. doi: 10.1016/j.cub.2020.11.028. Epub 2020 Dec 3.
Sexual selection results in sex-specific characters like the conspicuously pigmented extension of the ventral tip of the caudal fin-the "sword"-in males of several species of Xiphophorus fishes. To uncover the genetic architecture underlying sword formation and to identify genes that are associated with its development, we characterized the sword transcriptional profile and combined it with genetic mapping approaches. Results showed that the male ornament of swordtails develops from a sexually non-dimorphic prepattern of transcription factors in the caudal fin. Among genes that constitute the exclusive sword transcriptome and are located in the genomic region associated with this trait we identify the potassium channel, Kcnh8, as a sword development gene. In addition to its neural function kcnh8 performs a known role in fin growth. These findings indicate that during evolution of swordtails a brain gene has been co-opted for an additional novel function in establishing a male ornament.
性选择导致了性特化特征的出现，例如几种剑尾鱼属鱼类雄性个体腹鳍末端明显着色的延伸部分——“剑”。为了揭示剑形成的遗传结构，并鉴定与剑发育相关的基因，我们对剑转录组进行了特征描述，并结合了遗传图谱分析方法。结果表明，剑尾鱼的雄性装饰物是从尾鳍中具有性非二态性的转录因子预图案发育而来的。在构成独特的剑转录组并位于与该特征相关的基因组区域的基因中，我们鉴定出钾通道 Kcnh8 是一个剑发育基因。除了其在神经功能中的作用外，kcnh8 在鳍的生长中也起着已知的作用。这些发现表明，在剑尾鱼的进化过程中，一个大脑基因被共同用于在建立雄性装饰物中发挥新的额外功能。
