ESTERASE ACTIVITY IN RELATION TO GENOTYPES AT THE EST-α AND EST-β LOCI IN DROSOPHILA VIRILIS

On 22 homozygous genotypes which are different in the combination of isozyme alleles at the Est-α and Est-β loci, both highly polymorphic in natural populations, two kinds of esterase activities were compared. Most of the esterase activities are controlled by these two esterase loci. The activity is highest in the genotypes which have two active alleles at both Est-α and Est-β loci. The null strain which is homozygous for silent alleles at both loci has weakest activity, a part of which may be ascribed to other genetic systems. The activity of genotypes which are homozygous for active alleles at only Est-α or Est-β locus is between these two groups. Esterase activity increases additively in proportion to the number of active alleles at each locus.