Early Stages of XY Sex Chromosomes Differentiation in the Fish Hoplias malabaricus (Characiformes. Erythrinidae) Revealed by DNA Repeats Accumulation

Autor(es)

de Freitas, Natalia Lourenco ^[1] ; Hamid Al-Rikabi, Ahmed Basheer ^{[1, 2]} ; Carlos Bertollo, Luiz Antonio ^[1] ; Ezaz, Tariq ^[3] ; Yano, Cassia Fernando ^[1] ; de Oliveira, Ezequiel Aguiar ^[1] ; Hatanaka, Terumi ^[1] ; Cioffi, Marcelo de Bello ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Dept Genet & Evolucao, Sao Carlos, SP - Brazil

^[2] Friedrich Schiller Univ, Jena Univ Hosp, Inst Human Genet, Kollegiengasse 10, D-07743 Jena - Germany

^[3] Univ Canberra, Inst Appl Ecol, Canberra, ACT - Australia

• Tipo de documento: Artigo Científico
• Fonte: CURRENT GENOMICS; v. 19, n. 3, p. 216-226, 2018.
• Citações Web of Science: 9

Resumo

Background: Species with `young' or nascent sex chromosomes provide unique opportunities to understand early evolutionary mechanisms (e.g. accumulation of repetitive sequences, cessation of recombination and gene loss) that drive the evolution of sex chromosomes. Among vertebrates, fishes exhibit highly diverse and a wide spectrum of sex-determining mechanisms and sex chromosomes, ranging from cryptic to highly differentiated ones, as well as, from simple to multiple sex chromosome systems. Such variability in sex chromosome morphology and composition not only exists within closely related taxa, but often within races/populations of the same species. Inside this context, the wolf fish Hoplias malabaricus offers opportunity to investigate the evolution of morphologically variable sex chromosomes within a species complex, as homomorphic to highly differentiated sex chromosome systems occur among its different karyomorphs. Materials \& Methods: To discover various evolutionary stages of sex chromosomes and to compare their sequence composition among the wolf fish's karyomorphs, we applied multipronged molecular cytogenetic approaches, including C-banding, repetitive DNAs mapping, Comparative Genomic Hybridization (CGH) and Whole Chromosomal Painting (WCP). Our study was able to characterize a cryptically differentiated XX/XY sex chromosome system in the karyomorph F of this species. Conclusion: The Y chromosome was clearly identified by an interstitial heterochromatic block on the short arms, primarily composed of microsatellite motifs and retrotransposons. Additionally, CGH also identified a male specific chromosome region in the same chromosomal location, implying that the accumulation of these repeats may have initiated the Y chromosome differentiation, as well as played a critical role towards the evolution and differentiation of sex chromosomes in various karyomorphs of this species. (AU)

• Processo FAPESP: 14/22532-7 - Evolução cariotípica e de cromossomos sexuais em peixes neotropicais
• Beneficiário: Luiz Antonio Carlos Bertollo
• Modalidade de apoio: Auxílio à Pesquisa - Regular