Origin and differentiation of sex chromosomes: The conventional XX/XY system and its derived forms. Comparative analyzes in insect, fishes, and amphibian species

• Grant number: 23/06898-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: April 01, 2024
• End date: November 30, 2026
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Marcelo de Bello Cioffi
• Grantee: Jhon Alex Dziechciarz Vidal
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated scholarship(s): 24/19003-4 - Comparative Cytogenomics in Frogs: Large-scale genomic reorganization and the evolution of multiple sex chromosomes., BE.EP.DR

Abstract

This project aims to advance knowledge of the processes involved in the origin and differentiation of XX/XY and XY-derived systems of sex chromosomes considered atypical and of rare occurrence. For this purpose, were selected the insect (the beetle Omophoita octoguttata, carrier of giant XY sex chromosomes); the fish (the wolffish Hoplias malabaricus, carrier of an XY system where the X is differentiated by the accumulation of repetitions, and not the Y) and the amphibians (the frog Leptodactylus pentadactylus, carrier of an @X1-X6/BX1-Y6 system, where males have, in their meiosis, a giant ring-shaped chromosomal chain composed of 12 sex chromosomes) as models. The isolation and characterization of the satellite DNA library (satellitome) of males and females of these species will be carried out. Comparative analyzes of the chromosomal distribution pattern of these satellite DNAs between males and females of each species will allow investigating the chromosomal differentiation processes that occurred during the differentiation of these atypical systems. Additionally, sex-specific satellite DNA families will be chosen to study the homogenization and recombination rates of the various haplotypes (genomic analysis). In the case of the @X1-X6/BX1-Y6 multiple system, comparative analyzes of the chromosomal distribution pattern of these satellitomes, not only between males and females, but also in congeneric species will provide conditions to investigate the processes of chromosomal differentiation that occurred after the rearrangements which triggered the origin of this atypical sex system among vertebrates. The proposed analyzes will offer a promising opportunity to investigate the processes of sex chromosome differentiation, thus allowing a deeper understanding of their evolutionary processes. The project relies on the integration of a network of national and international researchers, equally interested in the proposed approach, enabling the execution of the proposed objectives.