TY - JOUR AB - The tra-1 gene is a terminal regulator of somatic sex in Caenorhabditis elegans: high tra-1 activity elicits female development, low tra-1 activity elicits male development. To investigate the function and evolution of tra- 1, we examined the tra-1 gene from the closely related nematode C. briggsae. Ce-tra-1 and Cb-tra-1 are unusually divergent. Each gene generates two transcripts, but only one of these is present in both species. This common transcript encodes TRA-1A, which shows only 44% amino acid identity between the species, a figure much lower than that for previously compared genes. A Cb-tra-1 transgene rescues many tissues of tra-1(null) mutants of C. elegans but not the somatic gonad or germ line. This transgene also causes nongonadal feminization of XO animals, indicating incorrect sexual regulation. Alignment of Ce-TRA-1A and Cb-TRA-1A defined several conserved regions likely to be important for tra-1 function. The phenotype differences between Ce-tra- 1(null) mutants rescued by Cb-tra-1 transgenes and wild-type C. elegans indicate significant divergence of regulatory regions. These molecular and functional studies suggest that evolution of sex determination in nematodes is rapid and genetically complex. AU - de Bono, Mario AU - Hodgkin, J. ID - 6161 IS - 2 JF - Genetics KW - amino acid sequence KW - article KW - caenorhabditis elegans KW - evolution KW - genetic variability KW - nonhuman KW - priority journal KW - sex determination KW - Amino Acid Sequence KW - Animals KW - Animals KW - Genetically Modified KW - Base Sequence KW - Caenorhabditis KW - Caenorhabditis elegans KW - Caenorhabditis elegans Proteins KW - DNA KW - Helminth KW - DNA-Binding Proteins KW - Evolution KW - Molecular KW - Female KW - Helminth Proteins KW - Membrane Proteins KW - Molecular Sequence Data KW - Mutagenesis KW - RNA KW - Messenger KW - Sequence Homology KW - Amino Acid KW - Sex Determination (Analysis) KW - Transcription Factors KW - Transgenes KW - Turner Syndrome KW - Animalia KW - Caenorhabditis KW - Caenorhabditis briggsae KW - Caenorhabditis elegans KW - Nematoda SN - 00166731 TI - Evolution of sex determination in Caenorhabditis: Unusually high divergence of tra-1 and its functional consequences VL - 144 ER -