Dynamics of chromosomal evolution in the genus Hypsiboas (Anura: Hylidae)

Abstract

ABSTRACT. Hylidae is one of the most species-rich families of anurans, and 40% of representatives in this group occur in Brazil. In spite of such remarkable diversity, little is known about this family and its taxonomical and systematic features. Most hylids have 2n = 24, even though most of the cytogenetic data are mainly obtained based on the conventional chromosomal staining and are available for only 16% of Hypsiboas species, a genus accounting for about 10% of the hylid diversity. In this study, cytogenetic data of distinct species and populations of Hypsiboas were analyzed, and the evolutionary dynamics of chromosomal macro-and microstructure of these amphibians were discussed. Contrary to the conservativeness of 2n = 24, this genus is characterized by a high variation of chromosomal morphology with as much as 8 karyotype patterns. Differences in the number and location of nucleolus organizer regions and C-bands allowed the identification of geographical variants within nominal 7827 ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 13 (3): 7826-7838 (2014) Dynamics of chromosomal evolution in the genus Hypsiboas species and cytotaxonomical chromosomal markers. Comparative analyses revealed a strong phylogeographic relationship between chromosomal patterns in this group.

Variability of NOR patterns in European water frogs of different genome composition and ploidy level

“…In the endemic frog Proceratophrys boiei , NORs were located on different chromosome pairs, depending on geographical region of its distribution (Amaro et al 2012). Similar results were described in Physalaemu olfersii (Silva et al 2000), Hypsiboas (Carvalho et al 2014), Physalaemus cuvieri (Quinderé et al 2009), and in the Jefferson salamanders Ambystoma jeffersonianum (Bi et al 2009). …”

“…Possible mechanisms of the dispersion of NOR sites were translocations involving chromosomal segments containing NORs, however such chromosome rearrangements were connected with change in morphology of the NOR chromosomes (Lourenço et al 1998). Other possible mechanisms involved in dispersion of NORs in anuran genomes could be inversions, transpositions by mobile genetic elements containing NORs (Wiley et al 1989, Foote et al 1991, Lourenço et al 1998, Schmid et al 1995, King et al 1990, Bruschi et al 2012, Carvalho et al 2014) or rDNA amplification (Barth et al 2013). However, in the case of water frogs presented here, translocations involving chromosomal segments containing NORs on chromosomes 2 and 9 seems unlikely because chromosomes with extra NORs did not vary in length and shape from relative chromosomes in other individuals.…”

“…The number and position of NORs are species specific, although inter-individual variability of these regions has also been observed within species. In anuran amphibians, NORs detected by silver staining (Ag-NOR) revealed that most species, both from primitive and derived families, have only one pair of NOR-bearing chromosomes in their diploid karyotypes (Schmid 1982, King et al 1990, Birstein 1984, Vitelli et al 1982, Bruschi et al 2012, Carvalho et al 2014). The localization of NORs is conservative, i.e.…”

Chromosome evolution in Cophomantini (Amphibia, Anura, Hylinae)

“…lanciformis [ 48 ], and B . semilineata [ 49 ]. We additionally redescribe the karyotypes of eight species with new techniques: Ag-NORs ( B .…”

“…pulchella , and B . semilineata groups ([ 48 , 49 , 74 , 94 – 97 ], this study). In most species NORs are on a single pair of homomorphic chromosomes, a condition suggested as the ancestral state for Anura [ 98 ].…”