Cloned animals are prone to abnormal phenotypes such as enlarged tongue, fetal oversize, and progeria. In the present study, whole-genome bisulfite sequencing and mRNA sequencing were performed on tongue and biceps femoris muscles of cloned piglets with and without macroglossia, in an attempt to elucidate the epigenetic causes of the macroglossia phenotype. We identified 14 958 and 18 752 differentially methylated regions in the tongue and biceps femoris muscles, respectively, of macroglossia piglets and these correspond to 4574 and 4772 differentially methylated genes compared with the control group (piglets without macroglossia). Larger methylation difference was found in tongue muscle than in biceps femoris muscle. In total, 114 genes in tongue and 72 genes in biceps femoris muscles were found to be differentially expressed between the two groups. Of these differentially expressed genes in tongue muscle, 31 were also differentially methylated genes, among which DIO3 and ZIC1 were imprinting or predicted imprinting genes. These two and another six overlapping genes (ALDH1A2, MKX, MAB21L2, CA3, RANBP3L, and MYL10) are crucial factors involved in embryonic development or tissue and organ development. GO enrichment analysis suggested possible alteration of these processes. Our study provides novel molecular insights into the formation of macroglossia in cloned pigs.

中文翻译：

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巨舌克隆猪舌肌和股二头肌全基因组DNA甲基化及转录分析

克隆动物容易出现异常表型，例如舌头增大、胎儿过大和早衰。在本研究中，对具有和不具有巨舌症的克隆仔猪的舌头和股二头肌进行全基因组亚硫酸氢盐测序和 mRNA 测序，试图阐明巨舌症表型的表观遗传原因。我们在巨舌仔猪的舌头和股二头肌肌肉中分别鉴定了 14 958 和 18 752 个差异甲基化区域，与对照组（没有巨舌的仔猪）相比，这些区域对应于 4574 和 4772 个差异甲基化基因。在舌肌中发现比在股二头肌中更大的甲基化差异。总共，发现舌头中有114个基因和股二头肌中有72个基因在两组之间差异表达。这些舌肌差异表达基因中，31个也是差异甲基化基因，其中DIO3和ZIC1是印记或预测的印记基因。这两个和另外六个重叠基因（ALDH1A2、MKX、MAB21L2、CA3、RANBP3L和MYL10）是参与胚胎发育或组织和器官发育的关键因素。GO 富集分析表明这些过程可能发生改变。我们的研究为克隆猪巨舌的形成提供了新的分子见解。