Chromosome evolution in Lophyohylini (Amphibia, Anura, Hylinae)

Area of Science:

• Herpetology
• Cytogenetics
• Evolutionary Biology

Background:

• The Lophyohylini tribe comprises 87 treefrog species, yet cytogenetic data is scarce for most.
• Understanding chromosome evolution, including NOR position and banding patterns, is crucial for Lophyohylini phylogeny.

Purpose of the Study:

• To investigate chromosome evolution in the Lophyohylini tribe by analyzing karyotypes of 21 species.
• To evaluate the phylogenetic significance of chromosome characters such as NOR position, C-bands, and DAPI/CMA3 bands.

Main Methods:

• Karyotype analysis of 21 Lophyohylini species, with 16 studied for the first time.
• Phylogenetic analysis incorporating chromosome data (NOR position, C-bands, DAPI/CMA3 bands).

Main Results:

• Most species share a conserved karyotype (2n=24, FN=48), with exceptions noted in Phyllodytes edelmoi and Osteocephalus buckleyi.
• NOR location varied significantly, offering valuable phylogenetic markers; plesiomorphic state found in Trachycephalus, Itapotihyla langsdorffii, and Nyctimantis arapapa.
• Interstitial telomeric sequences and spontaneous rearrangements, potentially linked to fragile sites, were observed, suggesting novel evolutionary mechanisms.

Conclusions:

• NOR position is a key phylogenetic marker in Lophyohylini evolution.
• The presence of fragile sites or secondary constrictions may be a significant factor in the chromosome evolution of this treefrog group.
• Lophyohylini exhibits complex chromosome evolution, influenced by NOR variations and potentially rare cytogenetic phenomena.