Genome-wide associations, HERC2 and eye color

Sound familiar? Well, good things come in pairs. A few days ago I posted on a paper which used a linkage analysis to come to the conclusion that an SNP on HERC2 was responsible for the variation in eye color in Europeans. Some background, a gene, OCA2, was implicated in the variation in eye color, and it turns out that a few haplotypes on this locus can be used to predict with reasonable accuracy the phenotype in question. The paper I blogged a few days ago was a extension of the work of this work; the same group found that one SNP on HERC2 could actually better explain the variation (though there was a locus of minor affect on OCA2), and that that variation was caused by the regulation of expression of OCA2 by HERC2. Case closed, right? No, it's science, theoretically the case is always open; a continuing revelation so to speak. This paper covers the same topic, comes to similar conclusions, but explores some different methodology space:

...To date, the genetics of iris color is still not fully understood and is of interest, particularly in view of forensic applications. In three independent genome-wide association (GWA) studies of a total of 1406 persons and a genome-wide linkage study of 1292 relatives, all from the Netherlands, we found that the 15q13.1 region is the predominant region involved in human iris color. There were no other regions showing consistent genome-wide evidence for association and linkage to iris color. Single nucleotide polymorphisms (SNPs) in the HERC2 gene and, to a lesser extent, in the neighboring OCA2 gene were independently associated to iris color variation. OCA2 has been implicated in iris color previously. A replication study within two populations confirmed that the HERC2 gene is a new and significant determinant of human iris color variation, in addition to OCA2. Furthermore, HERC2 rs916977 showed a clinal allele distribution across 23 European populations, which was significantly correlated to iris color variation. We suggest that genetic variants regulating expression of the OCA2 gene exist in the HERC2 gene or, alternatively, within the 11.7 kb of sequence between OCA2 and HERC2, and that most iris color variation in Europeans is explained by those two genes....

Phew. That's it? A chart from the paper can actually illuminate the dark weeds of this verbiage....