Repetitive DNA probe linked to sex chromosomes in hybrids between Neotropical fish <i>Leporinus macrocephalus</i> and <i>Leporinus elongatus </i>(Characiformes, Anostomidae)

Abstract

Interspecific hybrids of fish can offer important advances in the zootechnical exploration of this animal group. However, hybrids can pose serious biological risks to the environment and natural populations, making genetic characterization and monitoring of hybrids produced in fish culture important concerns. In the present study, individuals of the hybrid ‘Piaupara’ were characterized by fluorescence in situ hybridization (FISH) using sex-specific probes to differentiate the respective parental contributions from female Leporinus macrocephalus (Piauçu) and male Leporinus elongatus (Piapara). The application of this technique demonstrated a difference in hybridization patterns between males and females of L. elongatus and L. macrocephalus, mainly due to the fact that the NOR-bearing chromosomes of L. elongatus contain some homology with the probe. This allowed us to detect a clear sex-specific distinction of the hybrid ‘Piaupara’, demonstrating that this technique is well-suited for the characterization of these hybrids. Moreover, this technique offers an important methodological advance for the study of diverse sex chromosome systems of Leporinus, supplying valuable information about the origin and establishment of a recently described sexual system in this genus.

Chromosomal features of nucleolar dominance in hybrids between the Neotropical fish Leporinus macrocephalus and Leporinus elongatus (Characiformes, Anostomidae)

“…When this repetitive DNA was used as a probe in L. elongatus metaphase chromosomes, homology between this sequence and the heterochromatic regions associated to the NOR was seen, beyond the regions in the sexual chromosomes described previously by Parise-Maltempi et al (2007). From this similarity, studies utilizing molecular techniques should be implemented to potentially identify the relationship and structural organization of these sequences associated with the nucleolar regions in L. elongatus, since these sequences were not observed in L. macrocephalus (Hashimoto et al 2009). …”

Cytogenetic Mapping of H1 Histone and Ribosomal RNA Genes in Hybrids between Catfish Species <b><i>Pseudoplatystoma corruscans</i></b> and <b><i>Pseudoplatystoma reticulatum</i></b>

“…Interspecific fish hybrids are important models for cytogenetic studies because they inherit 1 chromosome set of each parental species, which allows the identification of differences and/or similarities between the chromosomes of the parental species [Porto-Foresti et al, 2008;Hashimoto et al, 2009a] including sex chromosomes [Hashimoto et al, 2009b]. The fish hybrid between the species Pseudoplatystoma corruscans and P. reticulatum , known under the vernacular name 'ponto e vírgula', has great economic importance in the Brazilian aquaculture [Campos, 2010].…”

Chromosome mapping of retrotransposable elementsRex1andRex3inLeporinusSpix, 1829 species (Characiformes: Anostomidae) and its relationships among heterochromatic segments and W sex chromosome

“…[26][27][28][29][30][31][32] In the present study, retrotransposable elements in the Rex family were also abundant in other heterochromatic regions in Leporinus chromosomes, such as terminal positions and some interstitial segments. This distribution reflects the pattern expected for transposable elements distribution described by Kidwell,7 related to a low rate of recombination.…”

“…25 Recent studies of Leporinus have isolated, characterized, and correlated repetitive elements in these species to study the evolution of sex chromosomes, as well as to discriminate hybrid species. [26][27][28][29][30][31][32] Other studies have shown that repetitive sequences such as 5S rDNA may have different distributions among Leporinus species with or without heteromorphic sex chromosomes. 33 The high heterochromatic content in the chromosomes of Leporinus species, especially the sex chromosomes, demonstrates the presence of high numbers of repetitive sequences in the genomes of these species.…”

“…33 The high heterochromatic content in the chromosomes of Leporinus species, especially the sex chromosomes, demonstrates the presence of high numbers of repetitive sequences in the genomes of these species. [28][29][30][31][32]34 In the present study, cytogenetic mapping of the retrotransposable elements Rex1, Rex3, and Rex6 was performed in the chromosomes of Leporinus species to elucidate the activity and dispersion levels of these elements in genome of this genus. This analysis determined whether these elements are related to the heterochromatic regions of autosomes and sex chromosomes and whether their distributions are compatible with the hypothetical maintenance of a stable macrostructure in the karyotype of this genus.…”