Haplotype analysis of α-thalassemia chromosomes reveals heterogeneity and multiple founders in Ashkenazi Jews.

α-Thalassemia (α-thal) is among the world's most common single gene disorders, generally attributed to a selective advantage of heterozygotes against malaria mortality. A high frequency of -α deletion heterozygosity has been previously reported in Ashkenazi Jews despite lack of obvious malarial selection pressure in this population. Using haplotype and -α subtype analysis we analyzed a subset of -α homozygotes from various Israeli ethnic groups. We found a high frequency of the common Ia haplotype in Yemenite Jews and Arabs (54% and 13% respectively). Ashkenazi Jews exhibited a high frequency of IIIb alleles (67%) previously reported only in Aboriginal Australians and not found in other Israeli ethnicities. Both Yemenites and Ashkenazim carried the rare IIh alleles (18% and 15% respectively). These results may suggest multiple founder effects in Ashkenazi Jews as well a common founder for both Yemenite and Ashkenazi Jews.