An Electrophoretically Cryptic Alcohol Dehydrogenase Variant in Drosophila Melanogaster. 11. Post-Electrophoresis Heat-Treatment Screening of Natural Populations

The two common genetic variants of alcohol dehydrogenase in D. melanogaster, ADH-F and ADH-S, differ in substrate specificity and electrophoretic mobility. A third inherited variant, ADH-FCh.D., has a substrate specificity like ADH-S, an electrophoretic mobility like ADH-F, but much greater thermostability than either of the others. ADH-FCh.D. can be identified after post-electrophoresis heat treatment (15 s at 43°C) on cellulose acetate sheets. The AdhFCh?D ? allele has been found in 19 of 34 natural populations in Australasia but its frequency in these populations does not exceed 0·06. The partial correlation between AdhFCh ?D ? frequency and a maximum temperature variable is significant and positive among the Australasian populations although different climatic associations are found for a thermostable form of ADH-F in North America.