Meeting Abstract

P2.77  Saturday, Jan. 5  Are Hox genes involved in the genetic regulation of the novel abdominal appendages in male Sepsid fly, Themira biloba? HERATH, B. J.*; BOWSHER, J. H.; North Dakota State University, Fargo; North Dakota State University, Fargo bodini.herath@my.ndsu.edu

Evolutionary novel structures often provide a new function to the organism, but do not have a known homology. Even though modern insects lack any abdominal appendages in segments one through seven except for genitalia and cerci, some species of male sepsid flies (family Sepsidae) have evolved abdominal appendages on their fourth abdominal segment. These appendages are thought to be used during mating to stimulate the females. Research on the sepsid Themira biloba has found that their abdominal appendages are derived from ventral histoblast nests on the fourth segment. However, initial specification of the development of abdominal appendages in Sepsids has not been evaluated. Hox genes are important in segment specification in arthropods and defining antero-posterior axis of embryos. Further Hox genes are involved in regulating the expression of a variety of target genes which then may involve in significant developmental changes in organisms. Due to the Hox gene function in segment identity and histoblast specification in Drosophila, we propose that the bithorax complex of Hox genes are potential candidates for the development of abdominal appendages in the sepsid species, T. biloba. We hypothesize, (1) a shift in expression pattern of a bithorax gene may occur at the fourth abdominal segment making the phenotype different in T. biloba, and (2) there will be a change in the downstream targets of any of the three bithorax genes (Ultrabithorax, abdominal A, and Abdominal B) which resulted in the evolution of the abdominal appendage development in T. biloba.