Cerqueira Caio Cesar Silva de, Hünemeier Tábita, Gomez-Valdés Jorge, Ramallo Virgínia, Volasko-Krause Carla Daiana, Barbosa Ana Angélica Leal, Vargas-Pinilla Pedro, Dornelles Rodrigo Ciconet, Longo Danaê, Rothhammer Francisco, Bedoya Gabriel, Canizales-Quinteros Samuel, Acuña-Alonzo Victor, Gallo Carla, Poletti Giovanni, González-José Rolando, Salzano Francisco Mauro, Callegari-Jacques Sídia Maria, Schuler-Faccini Lavínia, Ruiz-Linares Andrés, Cátira Bortolini Maria
Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Laboratorio de Antropología Física, Departamento de Anatomía, Facultad de Medicina, Universidad Nacional Autónoma de Mexico, Mexico City, Mexico.
PLoS One. 2014 May 8;9(5):e96886. doi: 10.1371/journal.pone.0096886. eCollection 2014.
The understanding of the complex genotype-phenotype architecture of human pigmentation has clear implications for the evolutionary history of humans, as well as for medical and forensic practices. Although dozens of genes have previously been associated with human skin color, knowledge about this trait remains incomplete. In particular, studies focusing on populations outside the European-North American axis are rare, and, until now, admixed populations have seldom been considered. The present study was designed to help fill this gap. Our objective was to evaluate possible associations of 18 single nucleotide polymorphisms (SNPs), located within nine genes, and one pseudogene with the Melanin Index (MI) in two admixed Brazilian populations (Gaucho, N = 352; Baiano, N = 148) with different histories of geographic and ethnic colonization. Of the total sample, four markers were found to be significantly associated with skin color, but only two (SLC24A5 rs1426654, and SLC45A2 rs16891982) were consistently associated with MI in both samples (Gaucho and Baiano). Therefore, only these 2 SNPs should be preliminarily considered to have forensic significance because they consistently showed the association independently of the admixture level of the populations studied. We do not discard that the other two markers (HERC2 rs1129038 and TYR rs1126809) might be also relevant to admixed samples, but additional studies are necessary to confirm the real importance of these markers for skin pigmentation. Finally, our study shows associations of some SNPs with MI in a modern Brazilian admixed sample, with possible applications in forensic genetics. Some classical genetic markers in Euro-North American populations are not associated with MI in our sample. Our results point out the relevance of considering population differences in selecting an appropriate set of SNPs as phenotype predictors in forensic practice.
对人类色素沉着复杂的基因型 - 表型结构的理解，对人类的进化史以及医学和法医学实践都有着明确的意义。尽管此前已有数十个基因与人类肤色相关，但关于这一特征的知识仍不完整。特别是，针对欧洲 - 北美轴心以外人群的研究很少，而且直到现在，混合人群很少被考虑在内。本研究旨在填补这一空白。我们的目标是评估位于九个基因和一个假基因内的18个单核苷酸多态性（SNP）与两个具有不同地理和种族殖民历史的巴西混合人群（高乔人，N = 352；巴伊亚人，N = 148）的黑色素指数（MI）之间的可能关联。在总样本中，发现有四个标记与肤色显著相关，但只有两个（SLC24A5 rs1426654和SLC45A2 rs16891982）在两个样本（高乔人和巴伊亚人）中都始终与MI相关。因此，只有这两个SNP应初步被认为具有法医学意义，因为它们始终显示出这种关联，而与所研究人群的混合水平无关。我们并不排除其他两个标记（HERC2 rs1129038和TYR rs1126809）可能也与混合样本相关，但需要更多研究来证实这些标记对皮肤色素沉着的真正重要性。最后，我们的研究显示了一些SNP与现代巴西混合样本中的MI之间的关联，可能在法医遗传学中有应用。在我们的样本中，一些欧美人群中的经典遗传标记与MI无关。我们的结果指出了在法医学实践中选择合适的SNP作为表型预测指标时考虑人群差异的相关性。
