The Survey of the Frequency of Single and Triplicated α-Globin Gene Loci and Their Imbalance in Japanese
A survey of an interchromosoｍally unequal but homologous crossover in human α-globin gene cluster was performed with the DNA of the healthy Japanese adults. Of 200 haplotypes, 4 were found to be unusual α-globin gene clusters ; two were the triplicated[－α2－α2－α1－] generated by leftward crossover and the other two were the single [－α2α1(orα1)] created by rightward crossover. However, these identified haplotypes of single and triplicated a gene were not correspond in each to a reciprocal counterpart, produced by the same crossing over mechanism. Individuals with these unusual α-globin gene haplotypes showed neither clinical nor hematologic abnormalities.
