Meeting Abstract
The advancement of sequencing technologies has made it clear that sex chromosome systems are diverse across taxa. Sex chromosomes are under the influence of unique selective regimes due to their uneven distribution between sexes, causing them to undergo frequent turnover. Terrestrial isopods are ideal organisms for the study of sex chromosome evolution because their adult sex is amenable to manipulation by a simple laboratory procedure. The implantation of a viable androgenic gland stimulates the male developmental pathway, causing juvenile females to develop into fully functional adult males. By crossing two genetic females and analyzing the sex ratio of their offspring, the sex chromosome composition of the parents can be determined. We have successfully achieved sex-reversal of two juvenile females of the species Trachelipus rathkei. Our experimental crosses using these individuals and un-manipulated females yielded 100% female progeny. Such a sex ratio has not been seen in T. rathkei broods from wild-bred females of the same population, and cannot be attributed to infection by the feminizing bacteria Wolbachia. These results indicate that this population of T. rathkei uses an XX/XY sex chromosome system, with homogametic females. A previous paper concluded that T. rathkei has a ZZ/ZW sex chromosome system, using cytogenetic evidence. In the future, we plan to replicate this procedure on Porcellio scaber individuals and expand our successes in T. rathkei. We also plan to extract and sequence RNA from sex-reversed individuals to search for evidence of dosage compensation in this species. Finally, this discovery will help us refine our search for the T. rathkei sex chromosomes and sex-specific markers using previously gathered PacBio data.
