Identification and characterization of satellite DNAs in two-toed sloths of the genus Choloepus (Megalonychidae, Xenarthra)

Abstract

AbstractCholoepus, the only extant genus of the Megalonychidae family, is composed of two living species of two-toed sloths:Choloepus didactylusandC. hoffmanni. In this work, we identified and characterized the main satellite DNAs (satDNAs) in the sequenced genomes of these two species. SATCHO1, the most abundant satDNA in both species, is composed of 117 bp tandem repeat sequences. The second most abundant satDNA, SATCHO2, is composed of ~ 2292 bp tandem repeats. Fluorescence in situ hybridization inC. hoffmannirevealed that both satDNAs are located in the centromeric regions of all chromosomes, except the X. In fact, these satDNAs present some centromeric characteristics in their sequences, such as dyad symmetries predicted to form secondary structures. PCR experiments indicated the presence of SATCHO1 sequences in two other Xenarthra species: the tree-toed slothBradypus variegatusand the anteaterMyrmecophaga tridactyla. Nevertheless, SATCHO1 is present as large tandem arrays only inCholoepusspecies, thus likely representing a satDNA exclusively in this genus. Our results reveal interesting features of the satDNA landscape inCholoepusspecies with the potential to aid future phylogenetic studies in Xenarthra and mammalian genomes in general.