rs1800414

This genome-wide association study (GWAS) of pigmentary traits in East Asian populations (N=305 skin, N=342 iris) identifies a genome-wide significant signal for iris color in the OCA2 region, with rs1800414 (His615Arg) explaining 11.9%, 10.4%, and 6% of variation in b*, a*, and L* coordinates respectively. While no genome-wide significant signals were detected for skin pigmentation, rs2373391 in ZNF804B was replicated in independent Chinese samples (p=0.003).

This global population study of 3,432 individuals from 73 populations examined 21 SNPs in the OCA2-HERC2 region associated with eye and skin pigmentation. Blue-eye associated haplotypes (BEH1, BEH2, BEH3) were found at high frequencies in Europe, with BEH2 showing the strongest signal of selection. The East Asian-specific missense SNP rs1800414 (His615Arg) was associated with lighter skin pigmentation and showed strong evidence of positive selection in East Asian populations.

Genome-wide association studies and comparative genomics have identified major pigmentation loci (SLC24A5, SLC45A2, TYR, OCA2, MC1R, IRF4, TPCN2) showing evidence of strong natural selection in human populations. Light skin variants in Europeans and Asians underwent complete or near-complete selective sweeps, with SLC24A5 rs1426654 and SLC45A2 variants representing independent evolutionary mechanisms. Critical skin-lightening variants arose 11,000-30,000 years ago during human demographic expansion, driven by UV radiation exposure, vitamin D synthesis requirements, and possibly sexual selection.

A Spanish case-control study (131 melanoma patients, 245 controls) investigated 23 SNPs in six pigmentation genes (ASP, OCA2, TYR, TYRP1, SILV, SLC45A2) for melanoma susceptibility. The variant allele of SLC45A2 c.1122C>G (p.Phe374Leu, rs16891982) was associated with protection from melanoma (OR 0.41, 95% CI 0.24-0.70, adjusted P=0.008), validated by associations with dark hair, skin, and eye color.