Chromosome Mapping of U2 snDNA in Species of Leptodactylus (Anura, Leptodactylidae)

Abstract

Small nuclear RNA (snRNA) is a class of molecules involved in the processing of pre-mRNA and in regulatory cell processes. snRNAs are always associated with a set of specific proteins. The complexes are referred to as small nuclear ribonucleoproteins, and spliceosome U RNAs are their most common snRNA components. The repetitive sequences of U snDNAs have been cytogenetically mapped in several species of Arthropoda, fishes, and mammals; however, their distribution remains unknown in amphibians. Here, we show results of FISH mapping of U2 snDNA repetitive sequences in species of the amphibian genus <i>Leptodactylus</i> to reveal the distribution patterns of this sequence in their karyotypes. The probe hybridized in the metacentric chromosome pair 6 in <i>Leptodactylus fuscus</i>, <i>L. gracilis</i>, <i>L. latrans</i>, <i>L. chaquensis</i>, <i>L. petersii</i>, <i>L. podicipinus</i>, and <i>L. brevipes</i>. A different pattern was observed in <i>L. labyrinthicus</i> with hybridization signals in 4 chromosome pairs. The same localization of U2 gene sequences in most of the species analyzed suggests a relatively conserved pattern and a similarity of the chromosome 6 among these species of <i>Leptodactylus</i>.