The Mutations Previously Designated as Flightless-I³, Flightless-O² and Standby are Members of the W-2 Lethal Complementation Group at the Base of the X-Chromosome of Drosophila Melanogaster

Abstract

By using a well defined panel of chromosomal deficiencies, duplications and lethals, we have mapped three mutations causing flightlessness, flightless-I³, flighlless-O² and standby, to a single lethal complementation group (termed W-2) at the base of the X-chromosome of D. melanogaster. We also show that a fourth flightless mutation, termed grounded², previously mapped near to the base of the X-chromosome, is distal to the cytogenetic interval 18F to 20F. Mutants homozygous for ihcflightless-I³ flightless-0² and standby mutations exhibit abnormalities of myofibrillar arrangements in the indirect flight muscles. They have distorted Z-bands and the myofibrils are often displaced from their normal parallel arrangement. These viable flightless mutations are all hypomorphs since the homozygous deficiency of the W-2 X-chromosomal region is lethal to the organism.

Key Words:

• Deficiency mapping
• flightless mutants
• lethal mutations