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Gene expression dynamics during temperature-dependent sex determination in a sea turtle
Mónica Martínez-Pacheco1, Karina Díaz-Barba1, Rosario Pérez-Molina2
1Centro de Ciencias Genómicas, UNAM, CP62210, Cuernavaca, Mexico.
Developmental Biology
|June 24, 2024
Summary
Temperature influences sea turtle sex by affecting gene expression in embryos. Rapid changes in specific genes occur, but gonad development pathways are resilient, crucial for conservation efforts.
Area of Science:
- Marine Biology
- Developmental Biology
- Genetics
Background:
- Temperature-dependent sex determination (TSD) is known in turtles, but genetic factors in sea turtles are poorly understood.
- Climate change is increasing nesting beach temperatures, leading to skewed sex ratios and population biases in sea turtles.
Purpose of the Study:
- To investigate the genetic mechanisms underlying temperature-dependent sex determination in the olive ridley sea turtle.
- To identify key genes and pathways involved in temperature sensing and gonad development during embryonic stages.
Main Methods:
- RNA-sequencing (RNA-seq) analysis of embryonic tissues (gonads, brain, liver, mesonephros) from olive ridley sea turtles.
- Comparison of gene expression profiles at male-producing (26°C) and female-producing (33°C) incubation temperatures during the thermosensitive period (stages 21-26).
- Transcriptome analysis following temperature shifts in bi-potential gonads to identify rapid-response genes.
Main Results:
- Incubation temperature primarily influences broadly expressed genes via differential cell division rates, which then affects gonad-specific transcripts.
- Temperature-sensitive genes show rapid expression changes, particularly chromatin modifiers (JARID2, KDM6B), splicing factors (SRSF5), and transcription regulators (THOC2, DDX3X, CBX3).
- Overall gonad-specific pathways exhibit resilience to temperature changes, indicating a complex developmental fate determination.
Conclusions:
- Temperature primarily impacts global gene expression patterns, which are then channeled into gonad development for sex determination in sea turtles.
- Specific genes involved in temperature sensing respond quickly, but the overall developmental pathway for gonad differentiation is robust.
- Understanding these genetic pathways is vital for developing conservation strategies to mitigate climate change impacts on sea turtle populations.
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