English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background  The frogs of the Tribe Cophomantini present, in general, 2n = 24 karyotype, but data on  Aplastodiscus  showed variation in diploid number from 2n = 24 to 2n = 18. Five species were karyotyped, one of them for the first time, using conventional and molecular cytogenetic techniques, with the aim to perform a comprehensive comparative analysis towards the understanding of chromosome evolution in light of the phylogeny.    Results   Aplastodiscus perviridis  showed 2n = 24,  A. arildae  and  A .  eugenioi , 2n = 22,  A .  callipygius , 2n = 20, and  A .  leucopygius , 2n = 18. In the metaphase I cells of two species only bivalents occurred, whereas in  A. arildae ,  A .  callipygius , and  A .  leucopygius  one tetravalent was also observed besides the bivalents. BrdU incorporation produced replication bands especially in the largest chromosomes, and a relatively good banding correspondence was noticed among some of them. Silver impregnation and FISH with an rDNA probe identified a single NOR pair: the 11 in  A .  perviridis  and  A. arildae ; the 6 in  A. eugenioi ; and the 9 in  A. callipygius  and  A. leucopygius . C-banding showed a predominantly centromeric distribution of the heterochromatin, and in one of the species distinct molecular composition was revealed by CMA 3 . The telomeric probe hybridised all chromosome ends and additionally disclosed the presence of telomere-like sequences in centromeric regions of three species.    Conclusions  Based on the hypothesis of 2n = 24 ancestral karyotype for  Aplastodiscus , and considering the karyotype differences and similarities, two evolutionary pathways through fusion events were suggested. One of them corresponded to the reduction of 2n = 24 to 22, and the other, the reduction of 2n = 24 to 20, and subsequently to 18. Regarding the NOR, two conditions were recognised: plesiomorphy, represented by the homeologous small-sized NOR-bearing pairs, and derivation, represented by the NOR in a medium-sized pair. In spite of the apparent uniformity of C-banding patterns, heterogeneity in the molecular composition of some repetitive regions was revealed by CMA 3  staining and by interstitial telomeric labelling. The meiotic tetravalent might be due to minute reciprocal translocations or to non-chiasmatic ectopic pairing between terminal repetitive sequences. The comparative cytogenetic analysis allowed to outline the chromosome evolution and contributed to enlighten the relationships within the genus  Aplastodiscus .

Comparative karyotype analysis and chromosome evolution in the genus Aplastodiscus (Cophomantini, Hylinae, Hylidae)