Meeting Abstract
122.4 Monday, Jan. 7 Gene interactions in the sex differentiation pathway of Oncopeltus fasciatus (Heteroptera) LASLO, M*; ANGELINI, DR; American University; Colby College mlaslo09@gmail.com
The regulation and development of sex is a classic subject in developmental biology. The biological importance of sex suggests that sex determination mechanisms could be conserved among sexually reproducing species; however, developmental and genetic studies have revealed great diversity in the ways animals determine sex. Although insects are a diverse and numerous group of animals, sex determination mechanisms have only been examined in Holometabola. True bugs (Heteroptera), such as the milkweed bug, Oncopeltus fasciatus, are a diverse and species-rich order that diverged from Holometabola more than 300 million years ago. A conservative null model predicts that genes involved in sex determination in Drosophila melanogaster might also be involved in sexual development in the milkweed bug O. fasciatus. A model of sex determination in a hemimetabolous insect will offer a better understanding of the evolution of this process in insects. RNA interference is feasible and efficient during juvenile development in O. fasciatus, and knockdown of gene activity can be confirmed with quantitative RT-PCR. doublesex and transformer-2, two highly conserved genes, appear to have no role in O. fasciatus sexual development, although transformer-2 is varies throughout development and is dimorphically expressed in adults. fruitless, an early regulator of mating behavior in Drosophila and Blatella germanica, appears to play a role in O. fasciatus genital development. intersex, a downstream regulator of sexual development in Drosophila, is involved in development of internal reproductive structures and external genitalia. Expression of intersex is reduced in a fruitless RNAi background, suggesting that fruitless normally acts to promote intersex expression. These data expand our understanding of insect developmental diversity and suggest ancestral functions of some sex determination genes within Holometabola.
