In order to aid in the reconstruction of the Caenorhabditis briggsae sex determination pathway, for the purposes of studying the convergent evolution of hermaphroditism and mating system change in nematodes, Cb-tra mutants have been isolated through forward mutagenesis. Based on phenotype, genetic linkage, molecular linkage, and in some cases sequence analysis, the C. briggsae homologs of tra-1, tra-2, and possibly tra-3 have been identified. Upon further characterization, the function of the tra genes during sex determination between C. elegans and C. briggsae appears to be largely conserved. However, notable differences, with respect to the role of tra-1 and potentially the role of tra-3, have been observed between these two species. In addition, intra-species suppression of the putative tra-3 mutant (AF16 background) by genomic variants in the wild-type strain HK104 suggests that molecular interactions underlying sex determination are changing between these two C. briggsae populations.