Characterisation of HLA DQ alpha for forensic purposes. Allele and genotype frequencies in British Caucasian, Afro-Caribbean and Asian populations.

Allele and genotype frequencies for British Caucasian, Afro-Caribbean and Asian populations were determined for a total of over 600 unrelated individuals at the HLA-DQ alpha locus. These were analysed by polymerase chain reaction amplification of the DNA followed by hybridisation to allele specific oligonucleotide probes in a reversed dot-blot test. Six different alleles were detected and the allele distributions for the 3 populations analysed displayed significant differences. However, the British Caucasian genotypes were statistically very similar to previously published data from US Caucasians as were British Afro-Caribbean genotype frequencies with US Black data. In Caucasians the allele frequencies ranged from 5.2% to 26.9% with a power of discrimination of 0.93. DQ alpha genotype frequencies of Caucasian and Afro-Caribbean populations do not deviate from Hardy-Weinberg equilibrium. However, the Asian data displayed significant deviation due to excess homozygotes.