Meeting Abstract
The determination of a sex phenotype is a fundamental process in the development of sexually dimorphic organisms. Despite the ubiquity of sexually dimorphic animals, sex determination pathways vary greatly among them, indicating their subjectivity to evolution. However, little is known about their molecular and genetic details in most organisms other than mammals and Drosophila melanogaster. Hence, the heteropteran Oncopeltus fasciatus provides a novel model organism to the study of sex determination in insects. O. fasciatus has three orthologs of doublesex (dsx), the master regulator of sex determination in D. melanogaster, as well as single copies of other genes acting in fruit fly sex determination, such as intersex (ix). In D. melanogaster and many other insects, dsx regulates sexually dimorphic development via alternative splicing. RNAi of single orthologs in O. fasciatus do not alter sex determination, indicating potentially redundant functions of the orthologs. RNAi knockdowns of ix produce intersex phenotypes, demonstrating the factor’s crucial role in wildtype sex. We are conducting triple- and double-knockdowns of the dsx orthologs to further investigate the role of dsx in the sex determination of O. fasciatus as well as the potential redundant function of the three orthologs. Additionally, we are interested in the role that alternative splicing of dsx and ix plays in the sex determination of O. fasciatus and are conducting qRT-PCR analyses to investigate the presence of sex-, age-, and tissue-specific splicing isoforms. Our results will provide new detailed insights into the sex determination pathway of an under-studied but species-rich group of organisms.
