The Role of Methylation of DNA in Environmental Adaptation
The Role of Methylation of DNA in Environmental Adaptation
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DOI：
10.1093/icb/ict019
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发表时间：
2013-08-01
影响因子：
2.6
通讯作者：
Amdam, Gro V.
中科院分区：
文献类型：
--
作者：
Flores, Kevin B.;Wolschin, Florian;Amdam, Gro V.
DNA甲基化是影响基因表达模式的表观遗传机制。DNA甲基化标记有助于适应性表型变异，但在发育过程中会被抹去。因此，DNA甲基化在适应性进化中的作用尚不清楚。我们认为，环境诱导的DNA甲基化导致表型异质性，通过作用于表观遗传机制的力量为选择提供底物。例如，选择可以通过作用于DNA甲基化的基因组靶标的分子机制来改变环境诱导的DNA甲基化。另一种可能性是，环境诱导的但不可遗传的特定甲基化标记可能会影响优先存活，并导致相同基因组区域随着时间的推移而一致的甲基化。众所周知，DNA甲基化会增加胞嘧啶向胸腺嘧啶转变的可能性，不可遗传的适应性甲基化标记可以增加针对在几代人中一致标记的区域的突变可能性。这些突变中的一些可以从基因上捕捉到表观遗传标记的表型优势。因此，由DNA甲基化引起的基因组中选择性倾向的短暂改变最终可能通过突变成为可选择的遗传变异。我们使用来自不同分类群的例子为这些概念提供证据，但重点放在大规模DNA测序的实验数据上，这些测序揭示了蜜蜂双向选择后组间的遗传变异。
Methylation of DNA is an epigenetic mechanism that influences patterns of gene expression. DNA methylation marks contribute to adaptive phenotypic variation but are erased during development. The role of DNA methylation in adaptive evolution is therefore unclear. We propose that environmentally-induced DNA methylation causes phenotypic heterogeneity that provides a substrate for selection via forces that act on the epigenetic machinery. For example, selection can alter environmentally-induced methylation of DNA by acting on the molecular mechanisms used for the genomic targeting of DNA methylation. Another possibility is that specific methylation marks that are environmentally-induced, yet non-heritable, could influence preferential survival and lead to consistent methylation of the same genomic regions over time. As methylation of DNA is known to increase the likelihood of cytosine-to-thymine transitions, non-heritable adaptive methylation marks can drive an increased likelihood of mutations targeted to regions that are consistently marked across several generations. Some of these mutations could capture, genetically, the phenotypic advantage of the epigenetic mark. Thereby, selectively favored transitory alterations in the genome invoked by DNA methylation could ultimately become selectable genetic variation through mutation. We provide evidence for these concepts using examples from different taxa, but focus on experimental data on large-scale DNA sequencing that expose between-group genetic variation after bidirectional selection on honeybees, Apis mellifera.