Highly conserved Z and molecularly diverged W chromosomes in the fish genus Triportheus (Characiformes, Triportheidae)

Author(s)

Yano, C. F. ; Bertollo, L. A. C. ; Ezaz, T. ; Trifonov, V. ; Sember, A. ; Liehr, T. ; Cioffi, M. B.

• Document type: Journal article
• Source: HEREDITY; v. 118, n. 3, p. 276-283, MAR 2017.
• Web of Science Citations: 17

Abstract

The main objectives of this study were to test: (1) whether the W-chromosome differentiation matches to species' evolutionary divergence (phylogenetic concordance) and (2) whether sex chromosomes share a common ancestor within a congeneric group. The monophyletic genus Triportheus (Characiformes, Triportheidae) was the model group for this study. All species in this genus so far analyzed have ZW sex chromosome system, where the Z is always the largest chromosome of the karyotype, whereas the W chromosome is highly variable ranging from almost homomorphic to highly heteromorphic. We applied conventional and molecular cytogenetic approaches including C-banding, ribosomal DNA mapping, comparative genomic hybridization (CGH) and cross-species whole chromosome painting (WCP) to test our questions. We developed Z-and W-chromosome paints from T. auritus for cross-species WCP and performed CGH in a representative species (T. signatus) to decipher level of homologies and rates of differentiation of W chromosomes. Our study revealed that the ZW sex chromosome system had a common origin, showing highly conserved Z chromosomes and remarkably divergent W chromosomes. Notably, the W chromosomes have evolved to different shapes and sequence contents within similar to 15-25 Myr of divergence time. Such differentiation highlights a dynamic process of W-chromosome evolution within congeneric species of Triportheus. (AU)

• FAPESP's process: 14/22532-7 - Karyotype and sex chromosomes evolution in neotropical fishes
• Grantee: Luiz Antonio Carlos Bertollo
• Support Opportunities: Regular Research Grants