Human eye colour and HERC2, OCA2 and MATP.

Area of Science:

• Forensic genetics
• Human genetics
• Population genetics

Background:

• Predicting human eye color has forensic applications.
• Strong associations exist between eye color and specific SNPs in the HERC2 gene.
• Weaker associations between eye color and other genetic markers are also known.

Purpose of the Study:

• To investigate the predictive value of various combinations of SNP alleles in HERC2, OCA2, and MATP genes for human eye color.
• To compare these predictions with self-described eye colors in a Danish population.

Main Methods:

• Genotyping of single nucleotide polymorphisms (SNPs) in HERC2, OCA2, and MATP (SLC45A2) genes.
• Analysis of linkage disequilibrium between HERC2 SNPs rs1129038 and rs12913832.
• Diplotype analysis combining variations in HERC2 and OCA2 genes.
• Comparison of genetic predictions with self-reported eye color in 395 Danes.

Main Results:

• The HERC2 SNPs rs1129038 and rs12913832 showed the highest predictive value for distinguishing between light (blue, grey, green) and dark (brown, hazel) eye colors.
• Sequence variations in HERC2 (rs11636232, rs7170852), OCA2 (rs1800407), and MATP (rs16891982) provided additional predictive information.
• Diplotype analysis of three HERC2 variations and one OCA2 variation achieved the best discrimination between light and dark eyes, with a likelihood ratio of 29.3.

Conclusions:

• HERC2 gene SNPs are powerful predictors of human eye color, particularly for distinguishing between light and dark phenotypes.
• Combinations of SNPs, especially through diplotype analysis involving HERC2 and OCA2, significantly enhance prediction accuracy.
• These genetic markers hold substantial value for forensic investigations requiring eye color estimation.