Isolation of dominant XO-feminizing mutations in Caenorhabditis elegans: New regulatory tra alleles and an X chromosome duplication with implications for primary sex determination

J. Hodgkin, D. G. Albertson

Research output: Contribution to journalArticle


A strain of Caenorhabditis elegans was constructed that permits selection of dominant or sex-linked mutations that transform XO animals (normally male) into fertile females, using a feminizing mutation. tra-2(e2046gf), which by itself does not sexually transform XO males. Twenty-three mutations were isolated after chemical mutagenesis and found to fall into both expected classes (four dominant tra-I mutations and eight recessive xol-1 mutations) and novel classes. The novel mutations include 10 second-site mutations of tra-2, which are called eg mutations, for enhanced gain-of-function. The tra- 2(gf, eg) alleles lead to complete dominant transformation of XO animals from fertile male into fertile female. Also isolated was a duplication of the left end of the X chromosome, eDp26, which has dominant XO lethal and feminizing properties, unlike all previously isolated duplications of the X chromosome. The properties of eDp26 indicate that it carries copies of one or more numerator elements, which act as part of the primary sex-determination signal, the X:A ratio. The eDp26 duplication is attached to the left tip of the X chromosome in inverted orientation and consequently can be used to generate unstable attached-X chromosomes.

Original languageEnglish (US)
Pages (from-to)527-542
Number of pages16
Issue number2
StatePublished - Jan 1 1995


ASJC Scopus subject areas

  • Genetics

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