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Primary sex determination in the nematode C. elegans
1MRC Laboratory of Molecular Biology, Cambridge, UK.
Development (Cambridge, England)
|January 1, 1987
Summary
Most nematodes use XO/XX sex determination, but C. elegans uniquely has XX hermaphrodites. This study explores the genetic basis of hermaphrodite development and sex determination in nematodes.
Area of Science:
- Genetics
- Developmental Biology
- Nematology
Background:
- Most nematodes exhibit XO male and XX female sex determination.
- Caenorhabditis elegans presents an anomaly with XX hermaphrodites instead of females.
- Hermaphroditism in C. elegans arises from a modified male/female system allowing dual gamete production.
Purpose of the Study:
- To investigate the genetic mechanisms underlying sex determination in nematodes.
- To elucidate how C. elegans develops as a hermaphrodite.
- To explore the potential for creating artificial ZZ male/WZ female systems.
Main Methods:
- Analysis of autosomal regulatory genes responding to X-chromosome dosage.
- Investigating germ-line-specific control in sex determination pathways.
- Comparative analysis with Drosophila sex determination and dosage compensation.
Main Results:
- Identified a cascade of autosomal genes regulating sex development based on X-chromosome dosage.
- Demonstrated that mutations can create artificial ZZ male/WZ female sex determination systems.
- Confirmed X-chromosome dosage as the primary determinant of sex, similar to Drosophila.
- Observed dosage compensation mechanisms to equalize X-chromosome gene activity.
Conclusions:
- The hermaphrodite condition in C. elegans is a modification of a basic sex-determination system.
- Germ-line control and autosomal gene cascades are crucial for nematode sex development.
- X-chromosome dosage and dosage compensation play conserved roles in sex determination across species.