Sequences Associated With Human Iris Pigmentation

Corresponding author: Tony Frudakis, 900 Cocoanut Ave., Sarasota, FL 34236., tfrudakis{at}dnaprint.com (E-mail)

Communicating editor: P. J. OEFNER

To determine whether and how common polymorphisms are associated with natural distributions of iris colors, we surveyed 851 individuals of mainly European descent at 335 SNP loci in 13 pigmentation genes and 419 other SNPs distributed throughout the genome and known or thought to be informative for certain elements of population structure. We identified numerous SNPs, haplotypes, and diplotypes (diploid pairs of haplotypes) within the OCA2, MYO5A, TYRP1, AIM, DCT, and TYR genes and the CYP1A2-15q22-ter, CYP1B1-2p21, CYP2C8-10q23, CYP2C9-10q24, and MAOA-Xp11.4 regions as significantly associated with iris colors. Half of the associated SNPs were located on chromosome 15, which corresponds with results that others have previously obtained from linkage analysis. We identified 5 additional genes (ASIP, MC1R, POMC, and SILV) and one additional region (GSTT2-22q11.23) with haplotype and/or diplotypes, but not individual SNP alleles associated with iris colors. For most of the genes, multilocus gene-wise genotype sequences were more strongly associated with iris colors than were haplotypes or SNP alleles. Diplotypes for these genes explain 15% of iris color variation. Apart from representing the first comprehensive candidate gene study for variable iris pigmentation and constituting a first step toward developing a classification model for the inference of iris color from DNA, our results suggest that cryptic population structure might serve as a leverage tool for complex trait gene mapping if genomes are screened with the appropriate ancestry informative markers.

This article has been cited by other articles:

				P. Vogel, R. W. Read, R. B. Vance, K. A. Platt, K. Troughton, and D. S. Rice Ocular Albinism and Hypopigmentation Defects in Slc24a5-/- Mice Vet. Pathol., March 1, 2008; 45(2): 264 - 279. [Abstract] [Full Text] [PDF]

				S. Kishi, C. Cheng, D. French, D. Pei, S. Das, E. H. Cook, N. Hijiya, C. Rizzari, G. L. Rosner, T. Frudakis, et al. Ancestry and pharmacogenetics of antileukemic drug toxicity Blood, May 15, 2007; 109(10): 4151 - 4157. [Abstract] [Full Text] [PDF]

				R. L. Lamason, M.-A. P.K. Mohideen, J. R. Mest, A. C. Wong, H. L. Norton, M. C. Aros, M. J. Jurynec, X. Mao, V. R. Humphreville, J. E. Humbert, et al. SLC24A5, a Putative Cation Exchanger, Affects Pigmentation in Zebrafish and Humans Science, December 16, 2005; 310(5755): 1782 - 1786. [Abstract] [Full Text] [PDF]