Studies on mutation at esterase loci in Drosophila virilis. III. Genic variation in Est-α alleles produced by mutation experiments

抄録

With the highly polymorphic Est-α locus of Drosophila virilis, enquiry was made into its genetic structure. Electrophoresed were 1.47×10⁶ progeny raised from heterozygous females comprising thirty-two varieties of genotypes. In this study, 65 mutants were found to occur. Fifty-nine of these covered the full range of variation commonly observed in natural populations in Japan, whereas the remaining six were rather novel and in possession of new alleles not formerly recorded. Such a novelty in the behavior of the relevant genes may be understood as to indicate the occurrence of intragenic recombination. It has been suggested that the gene in question has some specific recombination sites, the regions of some intervening inert parts of genes (introns) or, if any, coding regions (exons) having a possible, specific base sequence where recombination is unaccompanied with base correction of the unpaired bases. Granting that intragenic recombination chiefly occurs within the region of introns, the most probable model is discussed to satisfactorily explain these results.