Molecular characterization and chromosomal distribution of Tc1/mariner transposons in Boana species (Anura, Hylidae).

Abstract

Transposable elements play an important role in determining the size and structure of eukaryotic genomes. Represented by several families, the Tc1/mariner superfamily is widely distributed in animal and plant genomes, and its structure has been characterized. Boana is a Neotropical genus of treefrogs, and despite the frequent 2n = 24 chromosomes found in its representatives, the karyotypic organization of the species cannot be considered conserved due to the scarcity of studies focusing on chromosomal mapping of repetitive DNA sequences. Here, Tc1/mariner elements were isolated and mapped on the chromosomes of three Boana species, followed by structural and phylogenetic analysis. The physical mapping revealed dispersed signals in euchromatin with small accumulations in some heterochromatic regions. All Tc1/mariner transposons isolated in this study presented high sequence integrity, suggesting that these elements had a recent invasion phase and are active in the host genomes of these frog species. Boana albopuntata and Boana faber presented a DD36E signature, while Boana prasina showed a new DD37E signature with a similar organizational structure and a close relationship with the known DD36E/Incomer family. These findings improve our understanding of the diversity of Tc1/mariner transposons and their role in the evolution of the hylid frog genome and karyotype.