Comparative Cytogenetic and Sequence Analysis of Genes in Three Species (Siluriformes: Loricariidae).

presents a wide karyotypic diversity, resulting from numeric and structural chromosomal rearrangements. It has been proposed that some genome-specific regions containing repetitive units could organize prone-to-break DNA sites in Loricariidae, triggering chromosomal rearrangements such as Robertsonian fusions (Rb fusions), centric fissions, translocations, and inversions. The tandemly repeats of the small nuclear RNAs (snRNAs) gene families are considered good cytogenetic markers for understanding chromosomal remodeling events among closely related species, but these snRNAs have been scarcely analyzed in . This study presented the nucleotide sequencing and comparative location of sequences from , cf. , and sp. (2n = 50, 52, and 50, respectively), aiming to provide information about snRNA clusters in the genome and chromosome evolution in . nucleotide sequences of presented identity to orthologous copies and folded their secondary structures correctly. localization and karyotyping of the three species revealed clustered copies of and gene families to a single chromosome site, one chromosome pair bearing sequence, and one main locus of sequence, besides scattered signals along the chromosomes. Previous studies related the participation of the gene families in centric fusion events, contributing to chromosome rearrangements and karyotype plasticity present in Loricariidae. In this study, homeologies in loci chromosomal locations were detected, indicating the occurrence of conserved sites of these gene families in these three species with 2n = 50 or 52 chromosomes.