Redpath Museum and Department of Biology, McGill University, Montreal, Quebec, Canada.
Smithsonian Tropical Research Institute, Panamá, República de Panamá.
Mol Biol Evol. 2019 Oct 1;36(10):2165-2170. doi: 10.1093/molbev/msz133.
Founder populations often show rapid divergence from source populations after colonizing new environments. Epigenetic modifications can mediate phenotypic responses to environmental change and may be an important mechanism promoting rapid differentiation in founder populations. Whereas many long-term studies have explored the extent to which divergence between source and founder populations is genetically heritable versus plastic, the role of epigenetic processes during colonization remains unclear. To investigate epigenetic modifications in founding populations, we experimentally colonized eight small Caribbean islands with brown anole lizards (Anolis sagrei) from a common source population. We then quantitatively measured genome-wide DNA methylation in liver tissue using reduced representation bisulfite sequencing of individuals transplanted onto islands with high- versus low-habitat quality. We found that lizard sex and habitat quality explained a significant proportion of epigenetic variation. Differentially methylated cytosines mapped to genes that encode proteins with functions likely to be relevant to habitat change (e.g., signal transduction, immune response, circadian rhythm). This study provides experimental evidence of a relationship between epigenetic responses and the earliest stages of colonization of novel environments in nature and suggests that habitat quality influences the nature of these epigenetic modifications.
奠基者群体在殖民新环境后常常迅速与源群体分离。表观遗传修饰可以介导对环境变化的表型响应，并且可能是促进奠基者群体快速分化的重要机制。尽管许多长期研究已经探讨了源群体和奠基者群体之间的分化在多大程度上是遗传可遗传的，而不是可塑性的，但殖民过程中表观遗传过程的作用仍不清楚。为了研究奠基者群体中的表观遗传修饰，我们用来自一个共同源群体的棕色安乐蜥（Anolis sagrei）实验性地殖民了八个小的加勒比岛屿。然后，我们通过对移植到具有高栖息地质量与低栖息地质量岛屿上的个体进行简化重亚硫酸盐测序，定量测量了肝脏组织中的全基因组 DNA 甲基化。我们发现蜥蜴的性别和栖息地质量解释了很大一部分表观遗传变异。差异甲基化的胞嘧啶映射到编码可能与栖息地变化相关的功能的蛋白质的基因（例如信号转导、免疫反应、昼夜节律）。这项研究提供了实验证据，证明了表观遗传反应与自然中新环境殖民的最早阶段之间存在关系，并表明栖息地质量影响这些表观遗传修饰的性质。
