Department of Genetics School of Life Sciences, SOKENDAI (Graduate University for Advanced Studies), Mishima, Japan.
Division of Human Genetics, National Institute of Genetics, Mishima, Japan.
Genome Biol Evol. 2018 Dec 1;10(12):3167-3175. doi: 10.1093/gbe/evy208.
Genomic duplication or loss can accelerate evolution because the number of repeats could affect molecular pathways and phenotypes. We have previously reported that the repeated region of filaggrin (FLG), a crucial component of the outer layers of mammalian skin, had high levels of nucleotide diversity with species-specific divergence and expansion and that it evolved under the birth-and-death model. We focused on hornerin (HRNR), a member of the same gene family that harbor similar tandem repeats as FLG, and examined the formation process of repeated regions and the evolutional model that best fit the HRNR repeated region in the crab-eating macaque (Macaca fascicularis), orangutan (Pongo abelii), gorilla (Gorilla gorilla), and chimpanzee (Pan troglodytes) and compared them with the human (Homo sapiens) sequence. Paar et al. (2011) and Takaishi et al. (2005) have different theories as to the formation of the repeated region of HRNR; both groups share the longest repeat length of 1,404 bp (quartic or longest unit), but they differed in the process. We identified the formation described by Paar et al. {[("39 bp (primary) × 9" × 2 (secondary)) × 2 (tertiary)] × 5 (quartic)} to be conserved in all species except the crab-eating macaque. We detected high nucleotide diversities between the longest repeats, which fits the birth-and-death model. We concluded that the high order repeat formation of HRNR was conserved in primates except the crab-eating macaque. As previously identified in FLG, the longest repeats have high levels of nucleotide diversity, which could contribute to phenotypic differences between closely related species.
基因组重复或缺失会加速进化，因为重复次数可能会影响分子途径和表型。我们之前曾报道过，丝聚合蛋白（FLG）的重复区域是哺乳动物皮肤外层的关键组成部分，其核苷酸多样性水平很高，具有物种特异性的分化和扩张，并且它是在诞生和死亡模型下进化的。我们关注的是角蛋白（HRNR），它是 FLG 相同基因家族的成员，具有类似的串联重复，我们检查了重复区域的形成过程和最适合食蟹猴（Macaca fascicularis）、猩猩（Pongo abelii）、大猩猩（Gorilla gorilla）和黑猩猩（Pan troglodytes）HRNR 重复区域的进化模型，并将其与人类（Homo sapiens）序列进行了比较。Paar 等人（2011 年）和 Takaishi 等人（2005 年）对 HRNR 重复区域的形成有不同的理论；这两个组都具有最长的重复长度 1404bp（四次或最长单位），但形成过程不同。我们确定了 Paar 等人描述的形成过程 {[("39 bp (primary) × 9" × 2 (secondary)) × 2 (tertiary)] × 5 (quartic)} 在除食蟹猴以外的所有物种中都保守。我们在最长重复之间检测到高核苷酸多样性，这符合诞生和死亡模型。我们得出结论，HRNR 的高序重复形成在除食蟹猴以外的灵长类动物中是保守的。如前在 FLG 中所确定的，最长的重复具有高水平的核苷酸多样性，这可能导致亲缘关系密切的物种之间表型差异。
