Data from: Population genetic structure and its implications for adaptive variation in memory and the hippocampus on a continental scale in food-caching black-capped chickadees

Food-caching birds rely on stored food to survive the winter and spatial memory has been shown to be critical in successful cache recovery. Both spatial memory and the hippocampus, an area of the brain involved in spatial memory, exhibit significant geographic variation linked to climate-based environmental harshness and the potential reliance on food caches for survival. Such geographic variation has been suggested to have a heritable basis associated with differential selection. Here, we ask whether population genetic differentiation and potential isolation among multiple populations of food-caching black-capped chickadees is associated with differences in memory and hippocampal morphology by exploring population genetic structure within and among groups of populations that are divergent to different degrees in hippocampal morphology. Using mitochondrial DNA and 583 AFLP loci, we found that population divergence in hippocampal morphology is not significantly associated with neutral genetic divergence or geographic distance, but instead is significantly associated with differences in winter climate. These results are consistent with variation in a history of natural selection on memory and hippocampal morphology that creates and maintains differences in these traits regardless of population genetic structure and likely associated gene flow.贮藏食物的鸟类依赖储粮越冬，而空间记忆已被证实对成功找回贮藏食物至关重要。空间记忆与调控空间记忆的大脑区域——海马体（hippocampus），均存在与气候介导的环境严酷性、以及生存对食物贮藏的依赖程度显著相关的地理变异。这类地理变异被认为具有与差异化选择相关的遗传基础。本研究旨在探究：多群贮藏食物的黑头山雀（black-capped chickadees）种群间的遗传分化与潜在种群隔离，是否与记忆及海马体形态差异存在关联。我们通过分析在海马体形态分化程度各异的种群组内及组间的种群遗传结构，来解答这一科学问题。本研究采用线粒体DNA（mitochondrial DNA）与583个扩增片段长度多态性位点（AFLP loci）开展分析，结果显示：海马体形态的种群分化与中性遗传分化及地理距离均无显著关联，却与冬季气候差异显著相关。上述结果与自然选择在记忆与海马体形态演化历史中产生的变异相符——这类选择塑造并维持了这些性状的差异，且不受种群遗传结构与潜在基因流的影响。