Integrating morphology and transcriptomics to understand the evolution of sexual development in lizards

• Grant number: 24/13853-6
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: January 15, 2025
• End date: January 14, 2026
• Field of knowledge: Biological Sciences - Morphology - Embryology
• Principal Investigator: Tiana Kohlsdorf
• Grantee: Juliana Luzete Monteiro
• Supervisor: Anthony Gamble
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Institution abroad: Marquette University, United States
• Associated to the scholarship: 22/07247-0 - Evolution of sex determination and sexual dimorphism in Squamata: relationships with ecological parameters and embryonic development, BP.DR

Abstract

Sex is a pervasive feature among animals and reproduction is one of the two components determining organismal fitness. Therefore, sex is a main factor in animal evolution. Sex determination is the commitment of the gonads to a female or male fate, and can be modulated by environmental (environmental sex determination or ESD) or genetic (genotypic sex determination or GSD) signals. GSD is further classified according to the mode of inheritance of the sex-determining factor: ZZ/ZW when females are the heterogametic sex, or XX/XY when the male is the heterogametic sex. Later production of sex hormones by the differentiated gonads is essential for sexual differentiation of traits that are important for the reproductive success. Vertebrates exhibit a diverse array of sex determination and sex chromosome systems, and some groups are notable for the high variability of this trait, as Squamate reptiles (lizards and snakes). Among lizards, geckos comprise lineages with temperature-dependent sex determination (TSD, a type of ESD), ZZ/ZW and XX/XY GSD systems, and multiple sex chromosome systems - providing an interesting biological system to understand the evolution of sexual development. Considering that the coordination between sex determination and subsequent sexual differentiation of various traits is essential to generate functional sexual phenotypes, we seek to assess whether sex determination and differentiation of the gonads and genitalia are molecularly and evolutionarily linked in geckos. We plan to determine the relative timing of sexual differentiation of both structures using morphological and transcriptomic data and to test if variation in the timing of differentiation of genitalia relative to the gonads is associated with a coupling of phenotypes to sex steroids by regulating the expression of androgen and estrogen receptors.