EVIDENCE SUPPORTING A SINGLE ORIGIN OF THE BETA-C-GLOBIN GENE IN BLACKS

  • 1 January 1985
    • journal article
    • research article
    • Vol. 37  (4) , 771-777
Abstract
In order to characterize the origin(s) of the .beta.C-globin gene in blacks, 25 chromosomes bearing this gene were characterized at 8 polymorphic restriction sites within the .beta.-globin gene cluster. Of the 25 chromosomes, 22 were identical at all sites and possessed a haplotype seen only infrequently among .beta.A-bearing chromosomes in black Americans. Two different haplotypes were observed among the 3 exceptional chromosomes. These haplotypes were identical to the most common .beta.C allele in the 3'' end of the .beta.-globin gene cluster, but differed in the 5'' region. Partial haplotype analysis on an additional 14 .beta.C alleles demonstrated complete association with the typical .beta.C-associated polymorphisms in the 3'' region of the cluster. These data can be most easily explained by a single origin of the mutation followed by spread of the mutation to other haplotypes through meiotic recombination 5'' to the .beta.-globin gene.