Meeting Abstract
The sex chromosomes of terrestrial isopods have a complex evolutionary history. This complexity may result from infection by the endosymbiotic bacteria Wolbachia, which can exert feminizing effects on male hosts in isopods. Over time, this pressure selects for novel sex chromosomes or sex determination processes in isopods. Being able to chart the sex specific regions of non-infected individuals provides a model for understanding the evolution of sex chromosomes. Using isopods presents a new model organism for testing and mapping the evolution of these unique sex chromosomes. The species of interest in this project, Porcellio scaber, has a ZZ/ZW sex determination system, similar to the species Armadillidium vulgare. However, phylogenetically, P. scaber is more closely related to Trachelipus rathkei, which has an XX/XY system. In addition, W-linked markers have been identified in the A. vulgare genome, but not in P. scaber, and so it cannot be determined if the P. scaber W chromosome is homologous to A. vulgare, or if it evolved independently. The ultimate purpose of the project is to determine what loci are associated with sex specific portions of the Porcellio scaber genome by testing for sex-specific PCR primers, and ultimately to understand how these regions influence development, anatomy, and behavior. This research has the potential to expand the potential range of isopods as model organisms for studies in the evolution of sex and sex chromosomes.
