Mutation is located within the 1.7kb initiator fragment in the first intron of abd-A, within the Kr binding site. This is the same substitution as in abd-AHab-2 though additional polymorphisms establish that the mutations were independent events.
Nucleotide substitution: G251A.
Dominant transformation of portions of T3 towards A2, haltere and/or third leg become wing material.
T3 leg and haltere discs are occasionally reduced in size relative to the other discs in the larva in abd-AHab-1 mutant larvae. This correlates with the loss of the corresponding disc derivatives in the adult. Histoblast-like cells are also sometimes detected near the T3 leg discs in mutant larvae.
Transforms third thoracic and first abdominal segment to second abdominal segment.
Bacher, Nov. 1966.