de Oliveira Mariannah Pravatti Barcellos, Deon Geize Aparecida, de Menezes Cavalcante Sassi Francisco, de Souza Fernando Henrique Santos, Goes Caio Augusto Gomes, Utsunomia Ricardo, Porto-Foresti Fábio, Vidal Jhon Alex Dziechciarz, da Silva Amanda Bueno, Ezaz Tariq, Liehr Thomas, de Bello Cioffi Marcelo
Evolutionary Cytogenetics Laboratory, Department of Genetics and Evolution, Federal University of São Carlos, São Carlos 13565-905, Brazil.
Fish Genomics and Conservation Laboratory, Faculty of Sciences, São Paulo State University, Bauru 01049-010, Brazil.
Int J Mol Sci. 2025 Jun 24;26(13):6039. doi: 10.3390/ijms26136039.
The wolf fish is a Neotropical species characterized by remarkable karyotypic diversity, including seven karyomorphs (KarA-G) with distinct sex chromosome systems. This study investigated the homologous XY (KarF) and XYY (KarG) sex chromosome systems present in this species by integrating cytogenetics and genomics to examine sex chromosomes' composition through characterization of repeatome (satellite DNA and transposable elements) and sex-linked markers. Our analysis indicated that both karyomorphs are little differentiated in their sex chromosomes content revealed by satDNA mapping and putative sex-linked markers. Both repeatomes were mostly composed of transposable elements, but neither intra- (male versus female) nor interspecific (KarF x KarG) variations were found. In both systems, we demonstrated the occurrence of sex-specific sequences probably located on the non-recombining region of the Y chromosome supported by the accumulation of sex-specific haplotypes of HmfSat10-28/HmgSat31-28. This investigation offered valuable insights by highlighting the composition of homologous XY and XYY multiple sex chromosomes. Although homologous, the large Y chromosome in KarF corresponds to two separate linkage groups (Y and Y) in KarG implying a specific meiotic arrangement involving the X chromosome in a meiotic trivalent chain. This scenario likely influenced recombination rates and, as a result, the genomic composition of these chromosomes.
狼鱼是一种新热带物种，其特征是具有显著的核型多样性，包括七种核型（KarA - G），具有不同的性染色体系统。本研究通过整合细胞遗传学和基因组学，研究了该物种中存在的同源XY（KarF）和XYY（KarG）性染色体系统，通过重复序列组（卫星DNA和转座元件）和性连锁标记的表征来检查性染色体的组成。我们的分析表明，通过卫星DNA图谱和假定的性连锁标记揭示，这两种核型在其性染色体含量上几乎没有差异。两个重复序列组主要由转座元件组成，但未发现内部（雄性与雌性）或种间（KarF×KarG）变异。在这两个系统中，我们都证明了可能位于Y染色体非重组区域的性别特异性序列的存在，这得到了HmfSat10 - 28/HmgSat31 - 28性别特异性单倍型积累的支持。这项研究通过突出同源XY和XYY多性染色体的组成提供了有价值的见解。尽管同源，但KarF中的大Y染色体对应于KarG中的两个独立连锁群（Y和Y），这意味着在减数分裂三价链中涉及X染色体的特定减数分裂排列。这种情况可能影响了重组率，结果也影响了这些染色体的基因组组成。
