For highly mobile species that nevertheless show fine-scale patterns of population genetic structure, the relevant evolutionary mechanisms determining structure remain poorly understood. The bottlenose dolphin (Tursiops truncatus) is one such species, exhibiting complex patterns of genetic structure associated with local habitat dependence in various geographic regions. Here we studied bottlenose dolphin populations in the Gulf of California and Pacific Ocean off Baja California where habitat is highly structured to test associations between ecology, habitat dependence and genetic differentiation. We investigated population structure at a fine geographic scale using both stable isotope analysis (to assess feeding ecology) and molecular genetic markers (to assess population structure). Our results show that there are at least two factors affecting population structure for both genetics and feeding ecology (as indicated by stable isotope profiles). On the one hand there is a signal for the differentiation of individuals by ecotype, one foraging more offshore than the other. At the same time, there is differentiation between the Gulf of California and the west coast of Baja California, meaning that for example, nearshore ecotypes were both genetically and isotopically differentiated either side of the peninsula. We discuss these data in the context of similar studies showing fine-scale population structure for delphinid species in coastal waters, and consider possible evolutionary mechanisms.

中文翻译：

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生态进化过程在墨西哥下加利福尼亚州附近的宽吻海豚、Tursiops truncatus 种群中产生多样性。


对于高度流动的物种，尽管如此，它们仍显示出种群遗传结构的精细尺度模式，但决定结构的相关进化机制仍然知之甚少。宽吻海豚（ Tursiops truncatus ）就是这样的物种之一，表现出与不同地理区域的当地栖息地依赖相关的复杂的遗传结构模式。在这里，我们研究了加利福尼亚湾和下加利福尼亚州附近太平洋的宽吻海豚种群，这些地区的栖息地结构高度结构化，以测试生态、栖息地依赖性和遗传分化之间的关联。我们使用稳定同位素分析（评估摄食生态）和分子遗传标记（评估种群结构）在精细地理尺度上研究了种群结构。我们的结果表明，至少有两个因素影响遗传和摄食生态的种群结构（如稳定同位素谱所示）。一方面，存在按生态类型区分个体的信号，其中一个比另一个在近海觅食更多。与此同时，加利福尼亚湾和下加利福尼亚州西海岸之间存在差异，这意味着，例如，半岛两侧的近岸生态型在基因和同位素上都存在差异。我们在类似研究的背景下讨论这些数据，这些研究显示了沿海水域中飞燕草物种的精细种群结构，并考虑了可能的进化机制。