Iris pigmentation as a quantitative trait: variation in populations of European, East Asian and South Asian ancestry and association with candidate gene polymorphisms.
In this study, we present a new quantitative method to measure iris colour based on high-resolution photographs. We applied this method to analyse iris colour variation in a sample of individuals of East Asian, European and South Asian ancestry. We show that measuring iris colour using the coordinates of the CIELAB colour space uncovers a significant amount of variation that is not captured using conventional categorical classifications, such as 'brown', 'blue' or 'green'. We tested the association of a selected panel of polymorphisms with iris colour in each population group. Six markers showed significant associations with iris colour in the European sample, three in the South Asian sample and two in the East Asian sample. We also observed that the marker HERC2 rs12913832, which is the main determinant of 'blue' versus 'brown' iris colour in European populations, is also significantly associated with central heterochromia in the European sample.
['Edwards|Melissa|M|', 'Cha|David|D|', 'Krithika|S|S|', 'Johnson|Monique|M|', 'Cook|Gillian|G|', 'Parra|Esteban J|EJ|']
D000293:Adolescent D000328:Adult D044466:Asians D005127:Eye Color D005260:Female D020662:Guanine Nucleotide Exchange Factors D006801:Humans D007498:Iris D007499:Iris Diseases D008297:Male D010859:Pigmentation Disorders D011110:Polymorphism, Genetic D019655:Quantitative Trait, Heritable D044767:Ubiquitin-Protein Ligases D044465:Whites
ancestry association Iris colour high-resolution photographs central heterochromia single-nucleotide polymorphisms