Predicting the eye and hair color from genotype became an established and widely used tool in forensic genetics, as well as in studies of ancient human populations. However, the accuracy of this tool has been verified on the West and Central Europeans only, while populations from border regions between Europe and Asia (like Caucasus and Ural) also carry the light pigmentation phenotypes. We phenotyped 286 samples collected across North Eurasia, genotyped them by the standard HIrisPlex-S markers and found that predictive power in Caucasus/Ural/West Siberian populations is reasonable but lower than that in West Europeans. As these populations have genetic ancestries different from that of West Europeans, we hypothesized they may carry a somewhat different allele spectrum. Thus, for all samples we performed the exome sequencing additionally enriched with the 53 genes and intergenic regions known to be associated with the eye/hair color. Our association analysis replicated the importance of the key previously known SNPs but also identified five new markers whose eye color prediction power for the studied populations is compatible with the two major previously well-known SNPs. Four out of these five SNPs lie within the HERС2 gene and the fifth in the intergenic region. These SNPs are found at high frequencies in most studied populations. The released dataset of exomes from Russian populations can be further used for population genetic and medical genetic studies. This study demonstrated that precision of the established systems for eye/hair color prediction from a genotype is slightly lower for the populations from the border regions between Europe and Asia that for the West Europeans. However, this precision can be improved if some newly revealed predictive SNPs are added into the panel. We discuss that the replication of these pigmentation-associated SNPs on the independent North Eurasian sample is needed in the future studies.

中文翻译：

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优化北欧人群的眼睛和头发颜色的遗传预测。

从基因型预测眼睛和头发的颜色已成为法医遗传学以及古代人群研究中已建立并广泛使用的工具。但是，此工具的准确性仅在西欧和中欧人身上得到了验证，而欧洲和亚洲之间的边界地区（如高加索和乌拉尔）的人口也携带着浅色表型。我们对整个北欧亚大陆收集的286个样本进行了表型分析，并通过标准HIrisPlex-S标记对它们进行了基因分型，发现高加索/乌拉尔/西西伯利亚人口的预测能力是合理的，但低于西欧人。由于这些人群的遗传祖先与西欧人不同，因此我们假设它们可能携带稍微不同的等位基因谱。从而，对于所有样品，我们都进行了外显子组测序，该测序进一步丰富了53种基因和已知与眼睛/头发颜色相关的基因间区域。我们的关联分析不仅重复了先前已知的关键SNP的重要性，而且还鉴定了五个新标记，其对研究人群的眼睛颜色预测能力与两个主要的先前众所周知的SNP兼容。这五个SNP中的四个位于HERС2基因内，第五个位于基因间区域。在大多数研究人群中，这些SNP的出现频率很高。来自俄罗斯人口的外显子组的已发布数据集可进一步用于人口遗传和医学遗传研究。这项研究表明，对于欧洲和亚洲边界地区的人群而言，从基因型预测眼睛/头发颜色的系统的精确度要比西欧人的略低。但是，如果将一些新发现的预测SNP添加到面板中，则可以提高此精度。我们讨论在未来的研究中需要在独立的北欧亚样本上复制这些与色素沉着相关的SNP。