Temperature Incubation Influences Gonadal Gene Expression during Leopard Gecko Development

Area of Science:

• Developmental Biology
• Genetics
• Reproductive Biology

Background:

• Sexual differentiation establishes physiological, anatomical, and metabolic differences beyond gonads.
• In leopard geckos (E. macularius), sex is determined by egg incubation temperature.
• The developmental decision of gender is likely polygenic, not controlled by a single gene.

Purpose of the Study:

• To investigate genes involved in gonadal sexual differentiation during the thermosensitive period in leopard geckos.
• To understand the genetic basis of temperature-dependent sex determination (TSD).

Main Methods:

• Analysis of gene expression in leopard gecko embryos at stage 30 during the labile phase of sex differentiation.
• Investigated known gonadal differentiation genes (e.g., WNT4, SOX9, DMRT1, Erα, Erβ, GnRH, P450 aromatase, PRL, PRL-R).
• Utilized differential display to identify other putatively sex differentiation-involved genes.

Main Results:

• Identified differential gene expression at stage 30 in embryos exposed to sex-determining temperatures.
• Confirmed differential expression of known gonadal differentiation genes.
• Discovered differential expression of genes involved in broader biological pathways (e.g., ALDOC, FREM1, PKM) beyond gonadal development.

Conclusions:

• Embryo exposure to sex-determining temperatures triggers differential expression of multiple genes.
• These genes impact not only gonadal differentiation but also various other biological pathways.
• Findings support the concept of sex-specific tissue and metabolic polarization occurring early in embryonic development.