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Dissection of Larval Zebrafish Gonadal Tissue
Published on: April 26, 2017
Evolution of sex-specific traits through changes in HOX-dependent doublesex expression.
Kohtaro Tanaka1, Olga Barmina, Laura E Sanders
1Department of Evolution and Ecology, University of California-Davis, Davis, California, United States of America.
Plos Biology
|September 3, 2011
Summary
Changes in the spatial regulation of the doublesex (dsx) gene, influenced by the Sex combs reduced (Scr) gene, drive the evolution of male-specific traits like Drosophila sex combs. This mechanism enables rapid phenotypic diversification across species.
Area of Science:
- Evolutionary developmental biology
- Genetics
- Animal development
Background:
- Sex-specific traits evolve frequently, but underlying genetic mechanisms remain unclear.
- Spatial regulation of sex determination pathways may explain trait evolution.
- Drosophila sex combs are a recent, diverse evolutionary innovation.
Purpose of the Study:
- Investigate the role of doublesex (dsx) in Drosophila sex comb development and evolution.
- Examine the regulation and function of dsx and Sex combs reduced (Scr).
- Understand how spatial gene regulation contributes to sex-specific trait evolution.
Main Methods:
- Comparative gene expression analysis of dsx and Scr in different Drosophila species.
- Examination of dsx regulation by Scr in sex comb development.
- Analysis of dsx expression patterns in species with and without sex combs.
Main Results:
- dsx expression in the presumptive sex comb region is activated by Scr.
- Male dsx isoform up-regulates Scr, creating a positive feedback loop for high expression in males.
- Precise spatial dsx regulation is crucial for sex comb position and morphology.
- Absence of dsx expression in homologous regions correlates with lack of sex combs.
- Independent evolution of male structures in other lineages shows similar gains in dsx expression, potentially regulated by Scr.
Conclusions:
- Changes in spatial regulation of sex-determining genes, like dsx, are a key driver of new sex-specific trait evolution.
- The interaction between dsx and Scr provides a mechanism for the origin and diversification of structures like sex combs.
- This regulatory mechanism contributes to significant phenotypic diversification in nature.
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