Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier (UPS), Station d'Ecologie Théorique et Expérimentale, UMR 5321, F-09200 Moulis, France.
CNRS, UPS, École Nationale de Formation Agronomique (ENFA), UMR 5174 EDB (Laboratoire Évolution & Diversité Biologique), 118 route de Narbonne, F-31062 Toulouse CEDEX 4, France.
Genes (Basel). 2021 Jan 16;12(1):107. doi: 10.3390/genes12010107.
Epigenetic components are hypothesized to be sensitive to the environment, which should permit species to adapt to environmental changes. In wild populations, epigenetic variation should therefore be mainly driven by environmental variation. Here, we tested whether epigenetic variation (DNA methylation) observed in wild populations is related to their genetic background, and/or to the local environment. Focusing on two sympatric freshwater fish species ( and ), we tested the relationships between epigenetic differentiation, genetic differentiation (using microsatellite and single nucleotide polymorphism (SNP) markers), and environmental distances between sites. We identify positive relationships between pairwise genetic and epigenetic distances in both species. Moreover, epigenetic marks better discriminated populations than genetic markers, especially in . In , both pairwise epigenetic and genetic distances were significantly associated to environmental distances between sites. Nonetheless, when controlling for genetic differentiation, the link between epigenetic differentiation and environmental distances was not significant anymore, indicating a noncausal relationship. Our results suggest that fish epigenetic variation is mainly genetically determined and that the environment weakly contributed to epigenetic variation. We advocate the need to control for the genetic background of populations when inferring causal links between epigenetic variation and environmental heterogeneity in wild populations.
表观遗传成分被假设对环境敏感，这应该使物种能够适应环境变化。因此，在野生种群中，表观遗传变异主要应该由环境变异驱动。在这里，我们测试了在野生种群中观察到的表观遗传变异（DNA 甲基化）是否与它们的遗传背景和/或当地环境有关。我们专注于两种同域淡水鱼类（ 和 ），测试了表观遗传分化、遗传分化（使用微卫星和单核苷酸多态性（SNP）标记）以及地点之间环境距离之间的关系。我们在两个物种中都发现了遗传和表观遗传差异之间的正相关关系。此外，表观遗传标记比遗传标记更好地区分了种群，尤其是在 中。在 中，两个种的成对的表观遗传和遗传距离都与地点之间的环境距离显著相关。尽管如此，当控制遗传分化时，表观遗传分化与环境距离之间的联系不再显著，表明这是非因果关系。我们的结果表明，鱼类的表观遗传变异主要是由遗传决定的，而环境对表观遗传变异的贡献较弱。我们主张在推断野生种群中表观遗传变异与环境异质性之间的因果关系时，需要控制种群的遗传背景。
