title: Sequences associated with human iris pigmentation.
abstract: 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.
authors.affiliation: DNAPrint Genomics, Sarasota, Florida 34236, USA. tfrudakis@dnaprint.com
authors.forename: Tony
authors.initials: T
authors.lastname: Frudakis
authors.forename: Matthew
authors.initials: M
authors.lastname: Thomas
authors.forename: Zach
authors.initials: Z
authors.lastname: Gaskin
authors.forename: K
authors.initials: K
authors.lastname: Venkateswarlu
authors.forename: K Suresh
authors.initials: KS
authors.lastname: Chandra
authors.forename: Siva
authors.initials: S
authors.lastname: Ginjupalli
authors.forename: Sitaram
authors.initials: S
authors.lastname: Gunturi
authors.forename: Sivamani
authors.initials: S
authors.lastname: Natrajan
authors.forename: Viswanathan K
authors.initials: VK
authors.lastname: Ponnuswamy
authors.forename: K N
authors.initials: KN
authors.lastname: Ponnuswamy
mesh_terms: D002879:Chromosomes, Human, Pair 10 / Q000235:genetics; D002884:Chromosomes, Human, Pair 15 / Q000235:genetics; D002892:Chromosomes, Human, Pair 22 / Q000235:genetics; D005060:Europe; D005127:Eye Color / Q000502:physiology*; D014644:Genetic Variation; D015894:Genome, Human; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D007498:Iris / Q000502:physiology*; D010858:Pigmentation / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide