Pheromones are important sexual signals in most animals, but research into their evolution is largely biased toward insects. Lampreys are a jawless fish with a relatively well-understood pheromone communication system, and they offer a useful opportunity to study pheromone evolution in a vertebrate. Once sexually mature, male sea lamprey (Petromyzon marinus) and likely other lampreys produce and release bile acids that act as sex pheromones. Spawning males do not feed and therefore produce bile acids primarily for sexual communication, whereas larvae produce the same bile acids but for digestion, offering an opportunity to compare the evolution of bile acids produced for sexual versus nonsexual functions. We profiled eight pheromone-related bile acids in livers from larvae and males and determined the effect of life stage on intra- and interspecific variation in bile acid production. Our results indicate less variation among males than larvae within P. marinus but more variation among species for males than larvae. We postulate that bile acid production in males is shaped by directional or stabilizing selection that reduces variance within P. marinus and directional or disruptive selection that promotes diversification across species. Although our results offer support for the role of sexual selection in the evolution of lamprey pheromones, they do not eliminate possible roles of other aspects of lamprey ecology.

中文翻译：

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在七Lamp鳗中作为性信息素的胆汁酸的种内和种间变异。

信息素在大多数动物中是重要的性信号，但对其进化的研究在很大程度上偏向昆虫。rey鱼是一种无颚鱼类，具有相对容易理解的信息素通讯系统，它们为研究脊椎动物信息素的进化提供了一个有用的机会。一旦性成熟，雄性海七lamp鱼（Petromyzon marinus）和其他七lamp鱼就会产生并释放出作为性信息素的胆汁酸。产卵的雄性不进食，因此主要产生用于性交的胆汁酸，而幼虫产生相同的胆汁酸但用于消化，从而提供了一个机会来比较为性功能和非性功能而产生的胆汁酸的演变。我们分析了幼虫和雄性肝脏中八种与信息素相关的胆汁酸，并确定了生命阶段对胆汁酸产生中种内和种间变异的影响。我们的研究结果表明，P。marinus中，雄性之间的变异小于幼虫，而雄性中的物种之间的变异大于幼虫。我们推测，雄性胆汁酸的产生是通过定向选择或稳定选择来减少，而该选择减少了海藻的变化，而定向选择或破坏性选择则可以促进跨物种的多样化。尽管我们的研究结果支持了性选择在七evolution信息素进化中的作用，但它们并未消除七lamp信息素其他方面的可能作用。marin，但雄性物种间的变异大于幼虫。我们推测，雄性胆汁酸的产生是通过定向选择或稳定选择来减少，而该选择减少了海藻的变化，而定向选择或破坏性选择则可以促进跨物种的多样化。尽管我们的研究结果支持了性选择在七evolution信息素进化中的作用，但它们并未消除七lamp信息素其他方面的可能作用。marin，但雄性物种间的变异大于幼虫。我们推测，雄性胆汁酸的产生是通过定向选择或稳定选择来减少，而该选择减少了海藻的变化，而定向选择或破坏性选择则可以促进跨物种的多样化。尽管我们的研究结果支持了性选择在七evolution信息素进化中的作用，但它们并未消除七lamp信息素其他方面的可能作用。