A long-term study on interactions between the Adh and αGpdh allozyme polymorphisms and the chromosomal inversion In(2L)t in a seminatural population of D. melanogaster

The Adh and alpha Gpdh allozyme loci (both located on the second chromosome) showed considerable fluctuations in allele frequencies in a seminatural population of Drosophila melanogaster during 1972-97. Both long-term and short-term fluctuations were observed. The short-term fluctuations occurred within almost all years and comparison of allele frequencies between winters and summers showed significantly higher Adh(S) (P <0.001) and alpha Gpdh(F) (P <0.01) allele frequencies in summers. Frequencies of these alleles were significantly positively correlated with environmental temperature, suggesting the adaptive significance of these allozyme polymorphisms. Frequency changes of the Odh locus (located on the third chromosome) showed no seasonal pattern and were not correlated with environmental temperature. Almost all short-term and long-term increases in Adh(S) frequency were accompanied by a corresponding decrease in alpha Gpdh(S) frequency (r = -0.82, P