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Sex determination: where environment and genetics meet
1Section of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA. crews@mail.utexas.edu
Evolution & Development
|December 21, 2002
Summary
Sex determination in vertebrates varies, influenced by genetics in mammals/birds and temperature in reptiles. Gene expression patterns reveal evolutionary links, and epigenetic factors shape individual sexuality beyond gonadal sex.
Area of Science:
- Comparative genomics
- Evolutionary biology
- Developmental biology
Background:
- Vertebrate sex determination mechanisms differ, with genetic control in mammals and birds, and temperature-dependent sex determination (TSD) in many reptiles.
- Understanding the genetic and environmental factors influencing sex determination and differentiation is crucial for evolutionary and developmental biology.
Purpose of the Study:
- To investigate the conservation and phylogenetic patterns of gene expression in vertebrate sex determination.
- To explore the role of epigenetic factors in shaping sexually dimorphic traits and individual variability.
Main Methods:
- Comparative analysis of gene expression patterns across different vertebrate taxa (mammals, birds, turtles, geckos).
- Investigating temperature-dependent sex determination (TSD) in turtles and epigenetic influences on sexual traits in geckos.
Main Results:
- Evidence for conserved genetic pathways in sex determination across vertebrates, with turtles showing phylogenetic similarities to mammals.
- Gene expression patterns in turtles suggest closer evolutionary relationships to mammals than to birds or crocodilians.
- Epigenetic factors significantly influence the development of sexually dimorphic behaviors and individual variability, particularly in species like the leopard gecko.
Conclusions:
- Sex determination in vertebrates involves both conserved genetic mechanisms and environmentally influenced pathways.
- Phylogenetic analysis of gene expression provides insights into the evolutionary history of sex determination.
- Distinction between gonadal sex and individual sexuality is critical, with epigenetics playing a key role in shaping the latter.
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