 Korea is the major recent source of Japanese genes, by the Yayoi period that lasted from 3000 to 1600 years ago approximately 3/4ths of Japanese genetic makeup is attributed to this migration.And yet there is trace DR3-DQ2 in Japanese, none in the Ainu nor many other indigeonous Siberian groups.When dealing with haplotypes, if one assumes that linkage disequilibrium is random, then one can estimate the time of equilibration based on the size of the haplotype, the A-B-DR haplotype is over 2 million nucleotides in length.