Durso Danielle Fernandes, Bydlowski Sergio Paulo, Hutz Mara Helena, Suarez-Kurtz Guilherme, Magalhães Tiago R, Pena Sérgio Danilo Junho
Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Laboratório de Genética e Hematologia Molecular, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
PLoS One. 2014 Jan 8;9(1):e83926. doi: 10.1371/journal.pone.0083926. eCollection 2014.
The Brazilian population was formed by extensive admixture of three different ancestral roots: Amerindians, Europeans and Africans. Our previous work has shown that at an individual level, ancestry, as estimated using molecular markers, was a poor predictor of color in Brazilians. We now investigate if SNPs known to be associated with human skin pigmentation can be used to predict color in Brazilians. For that, we studied the association of fifteen SNPs, previously known to be linked with skin color, in 243 unrelated Brazilian individuals self-identified as White, Browns or Blacks from Rio de Janeiro and 212 unrelated Brazilian individuals self-identified as White or Blacks from São Paulo. The significance of association of SNP genotypes with self-assessed color was evaluated using partial regression analysis. After controlling for ancestry estimates as covariates, only four SNPs remained significantly associated with skin pigmentation: rs1426654 and rs2555364 within SLC24A5, rs16891982 at SLC45A2 and rs1042602 at TYR. These loci are known to be involved in melanin synthesis or transport of melanosomes. We found that neither genotypes of these SNPs, nor their combination with biogeographical ancestry in principal component analysis, could predict self-assessed color in Brazilians at an individual level. However, significant correlations did emerge at group level, demonstrating that even though elements other than skin, eye and hair pigmentation do influence self-assessed color in Brazilians, the sociological act of self-classification is still substantially dependent of genotype at these four SNPs.
巴西人口由美洲印第安人、欧洲人和非洲人这三种不同祖先根源的广泛混合而成。我们之前的研究表明，在个体层面，使用分子标记估计的血统并不能很好地预测巴西人的肤色。我们现在研究已知与人类皮肤色素沉着相关的单核苷酸多态性（SNP）是否可用于预测巴西人的肤色。为此，我们研究了15个先前已知与肤色相关的SNP在243名来自里约热内卢、自我认定为白人、棕色人种或黑人的非亲属巴西个体，以及212名来自圣保罗、自我认定为白人或黑人的非亲属巴西个体中的关联性。使用偏回归分析评估SNP基因型与自我评估肤色之间关联的显著性。在将血统估计作为协变量进行控制后，只有四个SNP仍与皮肤色素沉着显著相关：SLC24A5基因内的rs1426654和rs2555364、SLC45A2基因处的rs16891982以及TYR基因处的rs1042602。这些基因座已知参与黑色素合成或黑素小体转运。我们发现，这些SNP的基因型，以及它们在主成分分析中与生物地理血统的组合，在个体层面都无法预测巴西人的自我评估肤色。然而，在群体层面确实出现了显著的相关性，这表明尽管除皮肤、眼睛和头发色素沉着之外的其他因素确实会影响巴西人的自我评估肤色，但自我分类的社会学行为在很大程度上仍然依赖于这四个SNP的基因型。
