Sexual Dimorphic Expression of Dmrt1 in Adult Japanese Gecko (Gekko japonicus)

<p>Introduction: The Dmrt1 gene is essential for sex determination and gonadal development across vertebrates. Despite its established role in model species, its functional dynamics and seasonal regulatory patterns remain uncharacterized in Gekko japonicus, a key species for understanding reptilian reproductive strategies. This study thus aimed to (1) elucidate its structural characteristics, (2) analyze seasonal expression profiles and sexual dimorphism of Dmrt1, and (3) define its physiological roles in reproductive cyclicity. Methods: Total RNA was extracted from adult G. japonicus testes, and the full-length Dmrt1 transcript was obtained through 3′ and 5′ RACE. Bioinformatics predicted its properties, and phylogenetic analysis was conducted using PhyloSuite v1.2.3. RT-qPCR evaluated gjDmrt1 expression in male and female tissues and gonads. Results: The gjDmrt1-encoded protein is a hydrophilic nuclear protein with a conserved 54-amino acid DM domain, exhibiting high conservation among vertebrates. RT-qPCR shows significant differential expression in male tissues, sex dimorphism favoring males, and expression peaks in April with notable periodic fluctuations. Conclusion: This study offers critical insights into the characterization of the Dmrt1 gene in G. japonicus. The findings underscore its significant role in seasonal reproductive regulation and provide essential information for further investigation into the interactions between Dmrt1 and other candidate genes associated with gonad differentiation, as well as its regulatory mechanisms across varying environmental conditions. </p>