Physical mapping of (GATA) n and (TTAGGG) n sequences in species of Hypostomus (Siluriformes, Loricariidae)

Abstract

Hypostomus, a genus of Loricariidae, is one of the most diversified and widely distributed genera among fishes of South America (Weber 2003). It is the dominant genus of armoured catfish in Brazilian rivers (Weber 2003). Chromosomally, this group is highly diversified and studies of repetitive DNAs in these species are still in preliminary stages. Hypostomus karyotypes range from 54 chromosomes in H. plecostomus (Muramoto et al. 1968) to 84 chromosomes in Hypostomus sp. 2 (Cereali et al. 2008). Artoni and Bertollo (2001) consider the diploid number of 54 chromosomes as basal for Hypostominae, using Trichomycteridae as outgroup, suggesting that the chromosome evolution of Hypostomus occurred through centric fissions. Recently, Bueno et al. (2012) showed that other chromosomal rearrangements, such as inversions, deletions, duplications and heterochromatinization, could contribute to the chromosomal differentiation within the genus. Repetitive DNAs arranged in tandem are important tools in studies of taxonomic and evolutionary problems. These sequences could be associated with chromosomal rearrangement events (Wichman et al. 1991; Rosa et al. 2012; and others). According to Wichman et al. (1991), satellite DNAs rapidly diverge during evolution. Thereby, they are important for solving the taxonomic and evolutionary problems among related species.