A Brief Review of Sex Determination Mechanisms Across Reptile Families

Abstract

Sex determination in reptiles represents one of the most diverse and evolutionarily dynamic systems among vertebrates. Across different taxa, both temperature-dependent sex determination (TSD) and genotypic sex determination (GSD) have been reported, with varying degrees of chromosomal differentiation. However, the current literature on this subject is fragmented, covering a limited number of species and genera, and often lacking cohesive overviews at the family level. This review aims to synthesize the available data concerning the sex-determination mechanisms across major reptilian families, highlighting whether species exhibit TSD or GSD, and, in the latter case, what type of chromosomal determinism (XY, ZW, multiple systems) they possess. A visual summary compiling the known genetic determinism status for a broad spectrum of reptile genera is provided, serving as a practical reference for future research. The review also discusses the knowledge gaps and the methodological challenges that continue to hinder a comprehensive understanding of sex-determination evolution in reptiles.