Temperature-dependent sex determination, realized by hormonal dynamics with enzymatic reactions sensitive to ambient temperature

Abstract

Temperature-dependent sex determination (TSD) is adopted by many animal taxa, including reptiles and fishes. In some species, the eggs develop into females under a low hatching temperature, whereas they will develop into males under a high hatching temperature (called the FM-pattern). In other species, the eggs develop into males (or females) under a low (or high) hatching temperature (MF-pattern). Still, in other species, the eggs develop into females, males, or females, respectively, when under a low, intermediate, or high hatching temperature (FMF-pattern). In this paper, we study a mechanism for realizing TSD. Specifically, we explore a hypothesis that the temperature dependence of enzymatic reaction rates causes a clear switching of sex hormone levels with gradual change of temperature. Herein, we analyze a simple hormonal-dynamics with temperature-sensitive rates of enzymatic reactions included in the sex-determining gene-protein regulatory network. We first examined the cases in which the enzymatic reactions followed Arrhenius equation. The MF-pattern appeared when the rates of aromatase production and/or estradiol production depend more strongly on temperature than do the rates of their decay. By contrast, the FM-pattern appeared when the temperature dependence is stronger for the decay rates of aromatase and/or estradiol than their production rates. However, the FMF-pattern appeared only when some enzymatic reactions follow Berthelot-Hood equation, which exhibits a stronger temperature dependence under higher temperatures than Arrhenius equation. We discuss the possible mechanisms for TSD of FMF-pattern, including alternative splicing and post-translational modification.

Genome-Wide Characterization of Alternative Splicing Events and Their Responses to Cold Stress in Tilapia

“…AS participates in organogenesis (Anand et al, 2008), development (Yamaguchi and Iwasa, 2018), tissue identity (Baralle and Giudice, 2017;Cong et al, 2018), disease occurrence (Scotti and Swanson, 2016;Martinez-Montiel et al, 2018) and heavy metals, cold and heat, pathogen attacks (Christensen et al, 1992;Hopf et al, 1992;Ali and Reddy, 2008;Mazzucotelli et al, 2008) in eukaryotes.…”

Conflict theory of genomic imprinting in mammals

“…At this moment, there exists a big gap between these two subfields of biology, but in near future, studying the molecular and physiological basis of ecologically or evolutionary important phenomena would be one of the important branches of ecology and evolutionary biology. The attempts to analyze the ecological and evolutionary implications in the models which are based on the physiological mechanisms including gene regulatory network and hormonal dynamics would be one possibility toward this direction (e.g., Satake et al, ; Yamaguchi & Iwasa, , ).…”

Temperature-Dependent Alternative Splicing of Precursor mRNAs and Its Biological Significance: A Review Focused on Post-Transcriptional Regulation of a Cold Shock Protein Gene in Hibernating Mammals

“…Some genes including SRY-box9 ( Sox9 ), Wilms tumor 1 ( WT1 ) and doublesex and mab3-related transcription factor 1 ( Dmrt1 ) are involved in TSD [ 78 , 82 , 83 , 84 , 85 , 86 ]. Yamaguchi and Iwasa pointed out that temperature-dependent alternative splicing is a possible biological mechanism for temperature sensitivity [ 87 ]. In accordance, Sox9 in crocodiles, WT1 in turtles, and Dmrt1 in turtles and crocodiles are subjected to alternative splicing and play a role in sex determination [ 78 , 82 , 83 , 84 , 86 ].…”