Karyological study of Ololygon tripui (Lourenço, Nascimento and Pires, 2009), (Anura, Hylidae) with comments on chromosomal traits among populations

Abstract

To increase the number of cytogenetic characters used in Ololygon tripui systematics, we applied some cytogenetic techniques such as Giemsa, C- and NOR-banding, and (FISH)fluorescence in situ hybridization with 18S rDNA and repetitive microsatellite DNA probes to the study of four populations from Minas Gerais State (southeastern Brazil). All populations showed 2n = 24 and FN = 48, and chromosomal formula 8m + 10sm + 6st. (NORs)Nucleolar organizing regions were located on chromosome pair 6 in all populations, although in the Tripuí locality additional markings were observed on one homologue of chromosome pair 3. These patterns were partially congruent with results obtained using the 18S rDNA FISH probe. The microsatellites repetitive DNA (GA)15 and (CAT)10 probes accumulated predominantly in the terminal region of all chromosomes. Chromosome morphology and Ag-NOR were conserved among populations, a conserved pattern in Ololygon Fitzinger, 1843. Repetitive DNA FISH probes patterns were similar among populations, but they revealed species-specific differences when compared with other species of the genus Ololygon, suggesting that molecular cytogenetics are potentially more informative in karyologically conservative taxa.

Comparative analysis based on replication banding reveals the mechanism responsible for the difference in the karyotype constitution of treefrogs Ololygon and Scinax (Arboranae, Hylidae, Scinaxinae)

“…Nevertheless, a possible third karyotypic constitution that had been suggested by that author was not confirmed here or by Cardozo et al (2011) who studied a large sample of species of Scinax (lato sensu). Subsequent studies (Oliveira 2011, Nogueira et al 2015a, Nogueira et al 2015b, Peixoto et al 2015, Lourenço et al 2016, and Peixoto et al 2016 confirmed that the two chromosome constitutions remained invariably the same, indicating that the karyotypes are relatively conserved within each of the two taxonomic groups.…”

“…Additionally, the combined analysis with phylogeny allowed these authors to establish that the characteristic Ag-NORs marker in small pair 11, as exhibited by the species in the S. ruber clade, was considered a plesiomorphy, whereas the location in pair 6 in the species of the S. catharinae clade is a derivative condition. Only recently, a small number of species of Scinax (lato sensu) have had their karyotypic analyses extended through the use of more advanced cytogenetic techniques, such as investigation of the nature of repetitive regions using fluorochrome staining or fluorescent in situ hybridization (FISH) with microsatellite probes, and the location of ribosomal or telomeric sequences using the FISH technique (Oliveira 2011, Nogueira et al 2015a, Nogueira et al 2015b, Peixoto et al 2015, Peixoto et al 2016.…”

Comparative analysis based on replication banding reveals the mechanism responsible for the difference in the karyotype constitution of treefrogs Ololygon and Scinax (Arboranae, Hylidae, Scinaxinae)

“…Nevertheless, a possible third karyotypic constitution that had been suggested by that author was not confirmed here or by Cardozo et al (2011) who studied a large sample of species of Scinax ( lato sensu ). Subsequent studies (Oliveira 2011, Nogueira et al 2015a, Nogueira et al 2015b, Peixoto et al 2015, Lourenço et al 2016, and Peixoto et al 2016) confirmed that the two chromosome constitutions remained invariably the same, indicating that the karyotypes are relatively conserved within each of the two taxonomic groups.…”

“…Additionally, the combined analysis with phylogeny allowed these authors to establish that the characteristic Ag-NORs marker in small pair 11, as exhibited by the species in the S. ruber clade, was considered a plesiomorphy, whereas the location in pair 6 in the species of the S. catharinae clade is a derivative condition. Only recently, a small number of species of Scinax ( lato sensu ) have had their karyotypic analyses extended through the use of more advanced cytogenetic techniques, such as investigation of the nature of repetitive regions using fluorochrome staining or fluorescent in situ hybridization (FISH) with microsatellite probes, and the location of ribosomal or telomeric sequences using the FISH technique (Oliveira 2011, Nogueira et al 2015a, Nogueira et al 2015b, Peixoto et al 2015, Peixoto et al 2016). …”

Novos Registros Geográficos, Variação Morfológica e Notas de História Natural de Scinax tripui (Amphibia, Anura, Hylidae) na Mata Atlântica de Minas Gerais (Brasil)

“…Em descrições de outras espécies de Scinax, foram analisados exemplares de S. tripui procedentes de Minas Gerais, dos municípios de Belo Horizonte, Mariana, Nova Lima, Itabira, Ouro Branco, Sabará e Simonésia, e do Espírito Santo, do município de Patrimônio da Penha (Lourenço et al, 2013;Lourenço et al, 2014;Lourenço et al, 2016). Adicionalmente, Peixoto et al (2016) O estudo do cariótipo de Scinax tripui evidenciou que a maioria dos caracteres citogenéticos foi conservativa entre as populações e que a espécie diferiu de outras congêneres em relação à morfologia cromossômica e ao padrão de DNA repetitivo, provavelmente devido à evolução independente de S. tripui, resultados que corroboraram sua identidade taxonômica (Peixoto et al, 2016). Lourenço et al (2009) alocaram Scinax tripui no grupo de espécies de S. catharinae (Boulenger, 1888), o qual foi definido por Faivovich (2002), suportado por sinapormofias morfológicas putativas.…”