Molecular characterization of the Tribolium abdominal-A ortholog and implications for the products of the Drosophila gene.

The Drosophila homeotic selector gene abdominal-A is important for determinative decisions in the anterior abdomen. Insects vary considerably with respect to abdominal morphology, and changes in the function of homeotic selector genes and/or downstream genes under their control presumably have been important to the evolution of these differences. Mutations in Abdominal, the Tribolium ortholog of abdominal-A, have been described, and have more posterior homeotic transformations than do Drosophila variants. Here we present the organization of the Abdominal gene and the sequences of its predicted proteins, the first such report for a non-Drosophilid insect. Two predicted proteins share N-terminal sequences with those proposed to be synthesized by the Drosophila ortholog. In addition, we describe the distribution of Abdominal transcripts during embryogenesis. The Tribolium expression pattern closely resembles that of Drosophila, and does not account for the differences in mutant phenotypes.