An organizer controls the development of the "sword," a sexually selected trait in swordtail fish
An organizer controls the development of the "sword," a sexually selected trait in swordtail fish
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DOI：
10.1111/j.1525-142x.2008.00251.x
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发表时间：
2008-07-01
影响因子：
2.9
通讯作者：
Begemann, Gerrit
中科院分区：
文献类型：
--
作者：
Eibner, Cornelius;Pittlik, Silke;Begemann, Gerrit
剑尾鱼属（Poeciliidae）的雄性剑尾鱼拥有一把由尾鳍的几条彩色细长腹鳍射线组成的“剑”。剑是一种第二性征，是通过女性偏好的性选择而进化而来的。为了揭示从幼鱼尾鳍到剑的变态的发育机制，我们设计了一种移植方案来分析单个移植的鳍条的命运及其与侧翼鳍条的相互作用。这些实验提供了证据，证明存在以前未被识别的感应信号，该信号源自发展成两条最长剑射线的射线。这种“剑组织器”导致相邻的鳍条生长并融入剑中，并诱导在尾鳍背侧移植物中形成额外的、通常有色素的剑。我们证明，发展剑的潜力仅限于尾鳍的某些部分。我们的研究结果表明，剑尾鱼剑的进化需要获得两种发育机制：在胚胎或早期幼虫中建立未来剑鳐的信号传导能力，以及通过成年雄性鱼中的雄激素信号传导激活其信号传导能力。
Male swordtail fish of the genus Xiphophorus (Poeciliidae) possess a "sword" that is composed of several colored elongated ventral fin rays of the caudal fin. The sword is a secondary sexual trait that evolved through sexual selection by female preference. To uncover the developmental mechanisms underlying the metamorphosis from a juvenile caudal fin to the sword, we have devised a transplantation protocol to assay the fate of single transplanted fin rays and their interactions with flanking rays. These experiments provide evidence for the existence of a previously unrecognized inductive signal that originates in those rays that develop into the two longest sword rays. This "sword organizer" causes adjacent fin rays to grow and become integrated into the sword and induces the development of an additional, typically pigmented sword in grafts to the dorsal part of the caudal fin. We show that the potential to develop a sword is restricted to certain parts of the caudal fin. Our findings suggest that the evolution of swords in swordtails required the acquisition of two developmental mechanisms: the establishment of signaling competence in prospective sword rays in the embryo or early larva, and its activation through androgen signaling in adult male fish.