Data from: Genomic response to selection for predatory behavior in a mammalian model of adaptive radiation

If genetic architectures of various quantitative traits are similar, as studies on model organisms suggest, comparable selection pressures should produce similar molecular patterns for various traits. To test this prediction, we used a laboratory model of vertebrate adaptive radiation to investigate the genetic basis of the response to selection for predatory behavior and compare it with evolution of aerobic capacity reported in an earlier work. After 13 generations of selection, the proportion of bank voles (Myodes [=Clethrionomys] glareolus) showing predatory behavior was five times higher in selected lines than in controls. We analyzed the hippocampus and liver transcriptomes and found repeatable changes in allele frequencies and gene expression. Genes with the largest differences between predatory and control lines are associated with hunger, aggression, biological rhythms and functioning of the nervous system. Evolution of predatory behavior could be meaningfully compared with evolution of high aerobic capacity, because the experiments and analyses were performed in the same methodological framework. The number of genes that changed expression was much smaller in predatory lines and allele frequencies changed repeatably in predatory but not in aerobic lines. This suggests that more variants of smaller effects underlie variation in aerobic performance, whereas fewer variants of larger effects underlie variation in predatory behavior. Our results thus contradict the view that comparable selection pressures for different quantitative traits produce similar molecular patterns. Therefore, to gain knowledge about molecular-level response to selection for complex traits, we need to investigate not only multiple replicate populations, but also multiple quantitative traits.

正如模式生物相关研究所示，若多种数量性状（quantitative trait）的遗传架构（genetic architecture）相似，则相似的选择压力应能使不同性状呈现相近的分子模式。为验证这一预测，我们借助脊椎动物适应性辐射（adaptive radiation）的实验室模型，探究了捕食行为选择响应的遗传基础，并将其与此前一项研究中报道的有氧能力演化进行对比。经过13代选择后，表现出捕食行为的堤岸田鼠（Myodes [=Clethrionomys] glareolus）在选择系中的比例较对照组高出5倍。我们对海马体（hippocampus）与肝脏转录组（transcriptome）进行了分析，发现等位基因频率（allele frequency）与基因表达均出现了可重复的变化。捕食选择系与对照组间差异最为显著的基因，与饥饿感、攻击行为、生物节律以及神经系统功能密切相关。由于两项实验与分析采用了统一的方法学框架，因此捕食行为的演化可与高有氧能力的演化进行有意义的对比。捕食选择系中表达发生变化的基因数量远少于有氧能力选择系，且等位基因频率仅在捕食选择系中出现了可重复的变化，而在有氧能力选择系中则未出现此类变化。这表明，有氧能力的变异由更多效应量较小的遗传变异（genetic variant）所驱动，而捕食行为的变异则由更少效应量更大的遗传变异所支撑。因此，我们的研究结果与"针对不同数量性状的相似选择压力会产生相似分子模式"这一观点相悖。若要深入理解复杂性状在选择压力下的分子响应机制，我们不仅需要研究多个重复种群，还需探究多种不同的数量性状。