Evolution of sex determination in Caenorhabditis: Unusually high divergence of tra-1 and its functional consequences de Bono, Mario ; https://orcid.org/0000-0001-8347-0443 Hodgkin, J. amino acid sequence article caenorhabditis elegans evolution genetic variability nonhuman priority journal sex determination Amino Acid Sequence Animals Animals Genetically Modified Base Sequence Caenorhabditis Caenorhabditis elegans Caenorhabditis elegans Proteins DNA Helminth DNA-Binding Proteins Evolution Molecular Female Helminth Proteins Membrane Proteins Molecular Sequence Data Mutagenesis RNA Messenger Sequence Homology Amino Acid Sex Determination (Analysis) Transcription Factors Transgenes Turner Syndrome Animalia Caenorhabditis Caenorhabditis briggsae Caenorhabditis elegans Nematoda 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. Genetics Society of America 1996 info:eu-repo/semantics/article doc-type:article text http://purl.org/coar/resource_type/c_2df8fbb1 https://research-explorer.ista.ac.at/record/6161 de Bono M, Hodgkin J. Evolution of sex determination in Caenorhabditis: Unusually high divergence of tra-1 and its functional consequences. <i>Genetics</i>. 1996;144(2):587-595. eng info:eu-repo/semantics/altIdentifier/issn/00166731 info:eu-repo/semantics/altIdentifier/pmid/8889522 info:eu-repo/semantics/openAccess