Comparative Cytogenomics in Frogs: Large-scale genomic reorganization and the evolution of multiple sex chromosomes.

• Grant number: 24/19003-4
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: May 01, 2025
• End date: October 31, 2025
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Marcelo de Bello Cioffi
• Grantee: Jhon Alex Dziechciarz Vidal
• Supervisor: Qi Zhou
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Institution abroad: Zhejiang University, China
• Associated to the scholarship: 23/06898-0 - Origin and differentiation of sex chromosomes: The conventional XX/XY system and its derived forms. Comparative analyzes in insect, fishes, and amphibian species, BP.DR

Abstract

Anura represents the vertebrate group with the highest number of atypical multiple-sex chromosomes derived from sex-autosome translocations, which manifest as chain- or ring-shaped multivalents during meiosis. Such cases are observed in species from the genus Odorrana (Ranidae) and Leptodactylus (Leptodactylidae), despite having diverged at least 135 Mya. The Taiwanese frog Odorrana swinhoana exhibits a ring-shaped hexavalent formed by six chromosomes during male meiosis, indicating an X1-X5/Y1-Y5 sex chromosome system. In the genus Leptodactylus, a similar large ring-shaped meiotic chain is observed in at least two species (named L. pentadactylus and L. paraensis), albeit in a polymorphic state regarding the number of chromosomes involved, which ranges from eight, ten, and twelve. This BEPE project intends to conduct comparative cytogenomic investigations to check the hypothesis that these chromosomal rearrangements may have occurred non-randomly and examine if the breakpoints linked to the origin of these ring-shaped multivalents were convergently shared in both species. The proposed activities includes: i) immersive training in bioinformatic analysis for genome assembly and annotation; ii) identifying the translocated regions implicated in Odorrana swinhoana's ring-shaped multivalent formation; iii) examining for selection signatures in the rearranged regions; iv) developing Oligonucleotide-based probes specific to these regions; and v) performing comparative genomic analysis in Odorrana and Leptodactylus to identify ancestral linkage groups (ALG). Prof. Qi Zhou (Zhejiang University, China) was selected as a supervisor because he is a global expert in animal genomics and will provide the student with high-quality training and expertise in the application of cutting-edge genomic techniques used for comparative genomic assays. This training experience will be significantly relevant for the student's advancement and for the forthcoming research conducted in our laboratory, which is progressively integrating genomic analyses with chromosomal investigations within the emerging field of cytogenomics.