Abstract
LDH isozymes in the house fly were found to be highly polymorphic in natural populations of Japan. Of the five alleles observed, B1.60 was the predominant one in every population. From the frequency of 0.811 in the B1.60 allele in Hokkaido, the frequency declined gradually to 0.785 in Tohoku district and to 0.623 in other districts of southern Japan. The frequencies correlate positively with the latitude at which the samples were taken. The correlation between the allele frequency and the average temperatures was demonstrated. The data suggest a selective influence of temperatures on the relative frequencies of B1.60 in the polymorphic populations.
