Chromosomal recombination fragments multigene haplotypes as the distance to that ancestor increases in number of generations.

.The haplotype is nodal in Ireland but is also at high frequency in Switzerland, it has a subnode in the Pasiegos of northern Spain.

Parts of the haplotype are spread into East Asia and even appear within the New world's indigenous populations.

DR15:DQ6 frequencies peak in central Asia, and it is suspect that this may be a point of Eurasian spread westward into Europe.

DR15-DQ6 also shows an association with factors (including a genetic factor on chromosome 12p12) involved in familial multiple sclerosis[12][13] DR15-DQ6 is strongly associated with the development of choroidal neovascular lesions in presumed ocular histoplasmosis syndrome.