Data from: Evidence from pyrosequencing indicates that natural variation in animal personality is associated with DRD4 DNA methylation

Personality traits are heritable and respond to natural selection, but are at the same time influenced by the ontogenetic environment. Epigenetic effects, such as DNA methylation, have been proposed as a key mechanism to control personality variation. However, to date little is known about the contribution of epigenetic effects to natural variation in behaviour. Here, we show that great tit (Parus major) lines artificially selected for divergent exploratory behaviour for four generations differ in their DNA methylation levels at the dopamine receptor D4 (DRD4) gene. This D4 receptor is statistically associated with personality traits in both humans and nonhuman animals, including the great tit. Previous work in this songbird failed to detect functional genetic polymorphisms within DRD4 that could account for the gene–trait association. However, our observation supports the idea that DRD4 is functionally involved in exploratory behaviour but that its effects are mediated by DNA methylation. While the exact mechanism underlying the transgenerational consistency of DRD4 methylation remains to be elucidated, this study shows that epigenetic mechanisms are involved in shaping natural variation in personality traits. We outline how this first finding provides a basis for investigating the epigenetic contribution to personality traits in natural systems and its subsequent role for understanding the ecology and evolution of behavioural consistency.

人格特质具有可遗传性，且受自然选择作用，同时亦受到个体发育环境的影响。表观遗传效应（如DNA甲基化（DNA methylation））已被提出是调控人格特质变异的关键机制。然而迄今为止，学界对于表观遗传效应在行为自然变异中的贡献仍知之甚少。本研究发现，经4代人工选育以获得分化探索行为的大山雀（Parus major）品系，其多巴胺受体D4（dopamine receptor D4，DRD4）基因区域的DNA甲基化水平存在显著差异。该D4受体在人类及包括大山雀在内的非人类动物中，均与人格特质存在统计学关联。此前针对该鸣禽的相关研究未能在DRD4基因内检测到可解释该基因-性状关联的功能性遗传多态性。然而本研究结果支持如下观点：DRD4基因功能性地参与调控探索行为，但其作用由DNA甲基化所介导。尽管DRD4甲基化的跨代一致性背后的确切机制尚待阐明，但本研究证实表观遗传机制参与塑造了人格特质的自然变异。本研究还阐述了此项首创性发现如何为探究自然系统中人格特质的表观遗传贡献，以及其后续在理解行为一致性的生态学与进化机制中的作用提供了研究基础。