Chromosomal Differentiation of Hyla nana and Hyla sanborni (Anura, Hylidae) With a Description of NOR Polymorphism in H. nana

Abstract

Specimens of Hyla nana and Hyla sanborni from a syntopic population were studied cytogenetically. These species are morphologically very similar and are frequently misidentified, confused with each other. Both species had a diploid chromosome number, 2n = 30. However, the karyotypes of H. nana and H. sanborni differed considerably from each other in the number of submetacentric and telocentric chromosomes. The two species also differed in their primary NOR-bearing chromosomes (metacentric pair 13 in H. nana and telocentric pair 12 in H. sanborni). Additional nucleolus organizer regions (NORs) were detected by Ag-NOR staining and FISH in chromosome pairs 1, 5, 6, 12, and 14 in seven specimens of H. nana. Thus, a total of six patterns of NOR were identified. These differences in karyotype and in NOR location allowed the unambiguous identification of syntopic individuals of the two species. However, the chromosomal morphology of both species differed from that reported for populations from other geographic regions, suggesting that a systematic reevaluation of this group of Hyla may be necessary.

B-chromosomes in two Brazilian populations of Dendropsophus nanus (Anura, Hylidae)

“…The karyotype of 39 specimens of D. nanus from Nova Aliança and of five specimens from Botucatu showed 2n = 30 chromosomes ( Figure 1A), as previously described for a population from Nova Aliança (Medeiros et al, 2003). However, in four males from Nova Aliança (ZUEC 11673, 11651, 11652 and DZSJRP 1111) and nine males from Botucatu (ZUEC 12242, 12245, 12246, 12247, 12249, 12251, 12254, 12256 and 12261), the karyotype was 2n = 31 chromosomes (Table 1).…”

“…The specimens were identified according to Medeiros et al (2003), and were deposited in the "Prof. Adão José Cardoso" Museum of Natural History (ZUEC), of Univer- Chromosome preparations were obtained from intestinal and testicular cell suspensions, as described by Schmid (1978) and Schmid et al (1979) and analyzed after routine staining with a 10% Giemsa solution, C-banding (King, 1980), Ag-NOR staining (Howell and Black, 1980) and fluorescence in situ hybridization (FISH) (Viegas-Péquignot, 1992) with an rDNA probe. The FISH probe consisted of a recombinant HM123 plasmid containing a fragment of Xenopus laevis rDNA (Meunier-Rotival et al, 1979), which was biotin-labelled by nick translation reaction using a BioNick TM Labeling System (Invitrogen).…”

Cytogenetics of three Brazilian species of Eleutherodactylus (Anura, Leptodactylidae) with 22 chromosomes and re-analysis of multiple translocations in E. binotatus

“…These mechanisms include the transposition of mobile genetic elements, ribosomal cistron amplification and rDNA reinsertion errors during extra chromosomal amplification of ribosomal cistrons. Cases of additional labels detected in one of the homologues by FISH but not seen by silver-staining have also been described in Hyla chrysoscelis and H. versicolor (Wiley et al, 1989), H. nana (Medeiros et al, 2003), and Colostethus sp. aff.…”

Cytogenetic and random ampliied polymorphic DNA analysis of Leptodactylus species from rural and urban environments (Anura, Amphibia)

“…Despite that no significant difference was observed in morphology, the pattern of C-banding or NOR localization between the specimens from the two environments and the occurrence of chromosomal polymorphisms in different amphibian populations were related, involving especially the diploid number, NORs and constitutive heterochromatin (Ruiz et al, 1981;Silva et al, 1999Silva et al, , 2000Lourenço et al, 1998Lourenço et al, , 2003Medeiros et al, 2003;Rosa et al, 2003). Silva et al (2000) determined the location of the constitutive heterochromatin in specimens of the three populations of L. fuscus and four of L. ocellatus in Brazil and demonstrated distinct patterns in distribution of heterochromatin between them.…”