Abstract
Oplegnathus fasciatus and O. punctatus (Teleostei: Centrarchiformes: Oplegnathidae), are commercially important rocky reef fishes, endemic to East Asia. Both species present an X1X2Y sex chromosome system. Here, we investigated the evolutionary forces behind the origin and differentiation of these sex chromosomes, with the aim to elucidate whether they had a single or convergent origin. To achieve this, conventional and molecular cytogenetic protocols, involving the mapping of repetitive DNA markers, comparative genomic hybridization (CGH), and whole chromosome painting (WCP) were applied. Both species presented similar 2n, karyotype structure and hybridization patterns of repetitive DNA classes. 5S rDNA loci, besides being placed on the autosomal pair 22, resided in the terminal region of the long arms of both X1 chromosomes in females, and on the X1 and Y chromosomes in males. Furthermore, WCP experiments with a probe derived from the Y chromosome of O. fasciatus (OFAS-Y) entirely painted the X1 and X2 chromosomes in females and the X1, X2, and Y chromosomes in males of both species. CGH failed to reveal any sign of sequence differentiation on the Y chromosome in both species, thereby suggesting the shared early stage of neo-Y chromosome differentiation. Altogether, the present findings confirmed the origin of the X1X2Y sex chromosomes via Y-autosome centric fusion and strongly suggested their common origin.
Funder
National Natural Science Foundation of China
Project of Zhejiang Province of China
Subject
Inorganic Chemistry,Organic Chemistry,Physical and Theoretical Chemistry,Computer Science Applications,Spectroscopy,Molecular Biology,General Medicine,Catalysis
Reference122 articles.
1. Eschmeyer’s Catalog of Fishes: Genera, Species, References, California Academy of Sciences;Fricke,2019
2. Fish Taxonomy;Meng,1995
3. Relationship between Oplegnathus fasciatus and Oplegnathus punctatus revealed by mtDNA sequences;Xiao;Acta Ocean. Sin.,2011
4. Pronounced population genetic differentiation in the rock bream Oplegnathus fasciatus inferred from mitochondrial DNA sequences;Xiao;Mitochondrial DNA A,2016
5. First draft genome sequence of the rock bream in the family Oplegnathidae