Eye colour genetics have been extensively studied in humans since the rediscovery of Mendel's laws. This trait was first interpreted using simplistic genetic models but soon it was realised that it is more complex. In this study, we analysed eye colour variability in a Large White pig population (n = 897) and report the results of GWASs based on several comparisons including pigs having four main eye colour categories (three with both pigmented eyes of different brown grades: pale, 17.9%; medium, 14.8%; and dark, 54.3%; another one with both eyes completely depigmented, 3.8%) and heterochromia patterns (heterochromia iridis - depigmented iris sectors in pigmented irises, 3.2%; heterochromia iridum - one whole eye iris of depigmented phenotype and the other eye with the iris completely pigmented, 5.9%). Pigs were genotyped with the Illumina PorcineSNP60 BeadChip and GEMMA was used for the association analyses. The results indicated that SLC45A2 (on chromosome 16, SSC16), EDNRB (SSC11) and KITLG (SSC5) affect the different grades of brown pigmentation of the eyes, the bilateral eye depigmentation defect and the heterochromia iridis defect recorded in this white pig population respectively. These genes are involved in several mechanisms affecting pigmentation. Significant associations for the eye depigmented patterns were also identified for SNPs on two SSC4 regions (including two candidate genes: NOTCH2 and PREX2) and on SSC6, SSC8 and SSC14 (including COL17A1 as candidate gene). This study provided useful information to understand eye pigmentation mechanisms, further valuing the pig as animal model to study complex phenotypes in humans.

中文翻译：

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大型白猪虹膜色素沉着和异色症模式的全基因组关联研究。

自孟德尔定律重新发现以来，人眼颜色遗传学已被广泛研究。首先使用简单的遗传模型来解释此特征，但很快就意识到它更加复杂。在这项研究中，我们分析了大型白猪种群（n = 897）的眼睛颜色变异性，并基于几项比较报告了GWAS的结果，这些比较包括具有四种主要眼睛颜色类别的猪（三只具有不同棕色等级的有色眼睛的猪：苍白，17.9％；中度，14.8％；暗，54.3％；另一只双眼完全脱色，3.8％）和异色症模式（虹膜异色症-色素性虹膜中的虹膜部分脱色，3.2％；虹膜异色症-全眼虹膜色素去除表型和虹膜完全变色的另一只眼睛，占5.9％）。用Illumina PorcineSNP60 BeadChip对猪进行基因分型，并使用GEMMA进行关联分析。结果表明，SLC45A2（16号染色体上的SSC16），EDNRB（SSC11）和KITLG（SSC5）分别影响该白猪种群中不同程度的眼睛褐色色素沉着，双眼色素沉着缺陷和虹膜异色症缺陷。 。这些基因参与影响色素沉着的几种机制。还确定了两个SSC4区域（包括两个候选基因：NOTCH2和PREX2）以及SSC6，SSC8和SSC14（包括COL17A1作为候选基因）上的SNP的眼部脱色模式的重要关联。这项研究提供了有用的信息，以了解眼睛的色素沉着机制，进一步评价了将猪作为研究人类复杂表型的动物模型。