Iowa State Study Links Primary Cilia to Temperature-Dependent Sex Determination in Turtles

Researchers at Iowa State University, led by evolutionary biologist Nicole Valenzuela, have identified primary cilia—tiny antenna‑like cell structures—as possible sensors that help turtle embryos detect nest temperature, a key factor that determines sex. The study compared two species: painted turtles, which rely on temperature to set sex, and spiny softshell turtles, which use sex chromosomes. Analysis of gene expression and regulatory networks revealed 89 shared transcription‑factor hubs, with many of the most changed hubs associated with primary cilia. The findings suggest that primary cilia may translate thermal cues into developmental signals, influencing whether embryos develop as males or females. While the work advances basic understanding of reptile biology, it also connects to broader biomedical research, as primary cilia are implicated in human developmental disorders and diseases.