Transdisciplinary Research Organization for Subtropics and Island Studies, University of the Ryukyus, Okinawa, Japan.
J Hum Genet. 2012 Nov 26;57(11):700-8. doi: 10.1038/jhg.2012.96. Epub 2012 Aug 2.
Most studies on the genetic basis of human skin pigmentation have focused on people of European ancestry and only a few studies have focused on Asian populations. We investigated the association of skin reflectance and freckling with genetic variants of melanocortin 1 receptor (MC1R) gene in Japanese. DNA samples were obtained from a total of 653 Japanese individuals (ages 19-40 years) residing in Okinawa; skin reflectance was measured using a spectrophotometer and freckling status was determined for each individual. Lightness index (L*) and freckling status were not correlated with age, body mass index or ancestry (Ryukyuan or Main Islanders of Japan). Among the 10 nonsynonymous variants that were identified by direct sequencing of the coding region of MC1R, two variants--R163Q and V92M--with the derived allele frequencies of 78.6 and 5.5%, respectively, were most common. Multiple regression analysis showed that the 163Q allele and the presence of nonsynonymous rare variants (allele frequencies <5%) were significantly associated with an increase in sex-standardized skin lightness (L* of CIELAB (CIE 1976 (Lab*) color space)) of the inner upper arm. Relative to the 92V allele, the 92M allele was significantly associated with increased odds of freckling. This is the first study to show an association between the 163Q allele and skin reflectance values; this association indicated that light-toned skin may have been subjected to positive selection in East Asian people.
大多数关于人类皮肤色素遗传基础的研究都集中在欧洲血统的人群上，只有少数研究关注亚洲人群。我们在日本人中调查了皮肤反射率和雀斑与黑素皮质素 1 受体（MC1R）基因遗传变异的关联。从居住在冲绳的总共 653 名日本个体（年龄 19-40 岁）中获得 DNA 样本；使用分光光度计测量皮肤反射率，并确定每个个体的雀斑状态。明度指数（L*）和雀斑状态与年龄、体重指数或祖源（琉球或日本主岛人）无关。在直接测序 MC1R 编码区鉴定的 10 个非同义变异中，两种变异 - R163Q 和 V92M - 分别具有 78.6%和 5.5%的衍生等位基因频率，是最常见的。多元回归分析表明，163Q 等位基因和非同义稀有变异（等位基因频率 <5%）的存在与内上臂的性别标准化皮肤明度（CIELAB（CIE 1976（Lab*）颜色空间）的 L*）增加显著相关。与 92V 等位基因相比，92M 等位基因与雀斑发生的几率增加显著相关。这是第一项表明 163Q 等位基因与皮肤反射率值之间存在关联的研究；这种关联表明，浅色皮肤可能在东亚人群中受到了正向选择。
