Global mitochondrial DNA (mtDNA) methylation has been recently described in bovine and showed particular signatures in both gametes and embryos. Here, we investigated the distribution of mtDNA methylation through strand‐specific mapping of methylation sites to gain perspective on how epigenetic mechanisms can be involved in mitochondrial function. We demonstrate that in both oocytes and embryos, the frequency of methylation is biased towards the light strand (L‐strand), particularly in the gene bodies and in the region containing the L‐strand promoter (LSP). Methylation is not restricted to CpG nucleotides and is not symmetrical on both strands. This configuration reinforces the hypothesis of a specific epigenetic regulation of mtDNA, which is an important observation for the understanding of how mitochondrial function is regulated.

中文翻译：

---

线粒体表观遗传学：线粒体 DNA 的甲基化在牛卵母细胞和胚胎中是链偏向的。

最近在牛中描述了全球线粒体 DNA (mtDNA) 甲基化，并在配子和胚胎中显示出特殊的特征。在这里，我们通过甲基化位点的链特异性映射研究了 mtDNA 甲基化的分布，以了解表观遗传机制如何参与线粒体功能。我们证明，在卵母细胞和胚胎中，甲基化的频率都偏向于轻链（L 链），尤其是在基因体和含有 L 链启动子（LSP）的区域。甲基化不限于 CpG 核苷酸，并且在两条链上都不对称。这种配置强化了 mtDNA 特定表观遗传调控的假设，这是理解线粒体功能如何调控的重要观察结果。