Chromosomal location of retrotransposable REX 1 in the genomes in fiveProchilodus(Teleostei

Abstract

Transposable elements are repetitive DNA sequences comprising a group of segments able to move and carry sequences within the genome. Studies involving comparative genomics have revealed that most vertebrates have different populations of transposable elements with significant differences among species of the same lineage. Few studies have been conducted in fish, the most diverse group of vertebrates, with the objective to locate different types of transposable elements. Therefore, this study proposed to map the retrotransposable element Rex1 applying Fluorescent in situ Hybridization (FISH) in five species of the genus Prochilodus (Prochilodus argenteus, Prochilodus brevis, Prochilodus costatus, Prochilodus lineatus and Prochilodus nigricans). After the application of the Rex1 probe, scattered markings were found throughout the genome of analyzed species, and also the presence of small clusters located in the centromeric and telomeric regions coincident with the heterochromatin distribution pattern. This was the first description of the retrotransposable element Rex1 in Prochilodus genome seeking for a better understanding of the distribution pattern of these retrotransposons in the genome of teleost fish.

Highest Diploid Number Among Gymnotiformes: First Cytogenetic Insights into Rhabdolichops (Sternopygidae)

“…31,32 The Rex retroelements are widespread among the genomes of different fish lineages, and they have been mapped by in situ hybridization in numerous fish. 33,34 The distribution patterns observed for the Rex retroelements have been found to vary across different groups: they are compartmentalized in pericentromeric heterochromatic regions among Cichlidae, Prochilodontidae, and Tetraodontidae [35][36][37] ; they colocalize with ribosomal genes in some Cichlidae, Erythrinidae, and Loricariidae species [38][39][40] ; they are associated with sexual heterochromatin in Channichthyidae 41 and Anostomidae 33 ; and they are dispersed throughout the genome in many species of Erythrinidae, Artedidraconidae, Bathydraconidae, Bovichtidae, Nototheniidae, and Loricariidae. 32,39,41 The previous pattern was observed herein for the two studied species of Rhabdolichops (Sternopygidae).…”

First insights on the retroelement Rex1 in the cytogenetics of frogs

“…The Rex family is widespread in fishes and was already mapped to a number of fish karyotypes through in situ hybridization, providing valuable markers for karyotype comparisons (examples in [ 8 – 20 ]; for review, see [ 21 ]). For Anura, the only available reports on Rex sequences arose from studies not designed specifically for the analysis of this TE but rather from the sequencing of the whole genomes of the pipid Xenopus tropicalis [ 22 , 23 ] and the dicroglossid Nanorana parkeri [ 24 ; GenBank accession number: JYOU00000000.1], which are representatives of the non-neobatrachian and Ranoidea, respectively.…”