Variation between electrophoretically identical alleles at the alcohol dehydrogenase locus in Drosophila melanogaster.

A new variant of alcohol dehydrogenase (ADH 7lk) was found in a laboratory stock of Drosophila melanogaster. ADH in this stock had the same electrophoretic mobility as the F variant both on acrylamide and on agar. Activity levels were similar to the levels in F flies at temperature between 15 and 25 C. But while ADH F enzyme is inactivated rapidly at 40 C, ADH 7lk is still active. Also, ADH S is not inactivated at this temperature, but has a far lower activity per fly than ADH 7lk. Genetic analysis showed that the new variant is an allele of the Adh locus.