Evolutionarily conserved, DMRT1, encodes alternatively spliced transcripts and shows dimorphic expression during...

Area of Science:

• Reproductive Biology
• Developmental Biology
• Genetics

Background:

• The Dmrt1 gene plays a conserved role in male sexual development across vertebrates.
• Understanding Dmrt1 function in non-mammalian species provides insights into the evolution of sex determination.
• Calotes versicolor, a lizard species, offers a unique model for studying sexual differentiation due to its lack of chromosomal and temperature-dependent sex determination.

Purpose of the Study:

• To clone and characterize the Dmrt1 orthologue in Calotes versicolor (CvDmrt1).
• To investigate the expression patterns of CvDmrt1 during gonadal differentiation and in adult gonads.
• To elucidate the role of CvDmrt1 in the sexual differentiation of Calotes versicolor.

Main Methods:

• Cloning and characterization of the CvDmrt1 gene.
• Analysis of CvDmrt1 gene expression using techniques like in situ hybridization or RT-PCR.
• Examination of gonadal development stages in Calotes versicolor embryos and adults.

Main Results:

• CvDmrt1 encodes alternatively spliced transcripts.
• Expression initiates in genital ridge mesenchymal cells differentiating into Sertoli cells from day 3.
• Expression shifts to germ cells in both testis and ovary from day 25 onwards.
• Lack of expression in coelomic epithelium suggests distinct origins for Sertoli and granulosa cells.

Conclusions:

• CvDmrt1 plays a significant role in the testicular pathway of sexual differentiation in Calotes versicolor.
• The distinct expression patterns of CvDmrt1 support the hypothesis that Sertoli and granulosa cells originate from different precursors.
• CvDmrt1 is essential for sexual differentiation in a species lacking typical sex determination mechanisms.