Tabin Julius A, Aspiras Ariel, Martineau Brian, Riddle Misty, Kowalko Johanna, Borowsky Richard, Rohner Nicolas, Tabin Clifford J
Department of Genetics, Harvard Medical School, Boston, MA 02115, United States.
Department of Genetics, Developmental and Cell Biology, Iowa State University, 640 Sciences Hall II, Ames, IA 50011, United States.
Dev Biol. 2018 Sep 15;441(2):338-344. doi: 10.1016/j.ydbio.2018.04.017. Epub 2018 Apr 25.
Little is known about the genetic basis of behavioral choice, such as temperature preference, especially in natural populations. Thermal preference can play a key role in habitat selection, for example in aquatic species. Examining this behavior on a genetic level requires access to individuals or populations of the same species that display distinct temperature preferences. Caves provide a uniquely advantageous setting to tackle this problem, as animals colonizing caves encounter an environment that generally has a different, and far more stable, annual temperature than what is encountered on the outside. Here, we focus on cave and surface populations of Astyanax mexicanus, the Mexican tetra, and examine temperature preference and strength of temperature preference (reflected in the percent of time spent at the optimal temperature). We used a tank with a stable temperature gradient and automated tracking software to follow individual fish from each population. We found that distinct populations of A. mexicanus display differences in both temperature preference and strength of preference. Hybrid crosses established that these are multigenic traits that segregate independently from one another. Temperature preference in many aquatic animals is known to shift towards warmer temperatures following infection with parasites (akin to a fever response in humans). While surface fish infected by the ectoparasite Gyrodactylus turnbulli (a gill fluke) displayed a strong fever response, cavefish showed a significantly attenuated fever response. This work establishes A. mexicanus as a genetically tractable system in which differences in temperature preference can be studied in naturally evolved populations.
关于行为选择的遗传基础，例如温度偏好，我们所知甚少，尤其是在自然种群中。热偏好可能在栖息地选择中发挥关键作用，例如在水生生物中。在基因层面研究这种行为需要获取同一物种中表现出不同温度偏好的个体或种群。洞穴提供了一个独特的有利环境来解决这个问题，因为在洞穴中栖息的动物所遇到的环境，其年温度通常与外界不同，而且要稳定得多。在这里，我们聚焦于墨西哥丽脂鲤（Astyanax mexicanus），即墨西哥盲鱼的洞穴种群和地表种群，并研究温度偏好以及温度偏好强度（反映在处于最适温度的时间百分比上）。我们使用了一个具有稳定温度梯度的水箱和自动跟踪软件来追踪每个种群的个体鱼。我们发现，墨西哥丽脂鲤的不同种群在温度偏好和偏好强度上都存在差异。杂交实验表明，这些是多基因性状，它们彼此独立分离。已知许多水生动物在感染寄生虫后，其温度偏好会转向更温暖的温度（类似于人类的发烧反应）。虽然感染了体外寄生虫——特氏三代虫（一种鳃吸虫）的地表鱼表现出强烈的发烧反应，但洞穴鱼的发烧反应则明显减弱。这项研究将墨西哥丽脂鲤确立为一个基因易处理的系统，在这个系统中，可以在自然进化的种群中研究温度偏好的差异。
