Physical mapping of repetitive DNA suggests 2n reduction in Amazon turtles Podocnemis (Testudines: Podocnemididae)

Cytogenetic studies show that there is great karyotypic diversity in order Testudines (2n = 26-68), and that this may be mainly attributed to the presence/absence of microchromosomes. Members of the Podocnemididae family have the smallest diploid numbers of this order (2n = 26-28), which may be a de...

Full description

Saved in:
Bibliographic Details
Published in:PloS one 2018-05, Vol.13 (5), p.e0197536-e0197536
Main Authors: Cavalcante, Manoella Gemaque, Bastos, Carlos Eduardo Matos Carvalho, Nagamachi, Cleusa Yoshiko, Pieczarka, Julio Cesar, Vicari, Marcelo Ricardo, Noronha, Renata Coelho Rodrigues
Format: Article
Language:English
Subjects:
Animals
Biology and life sciences
Chromosome mapping
Chromosomes
Conservation
Conserved sequence
Deoxyribonucleic acid
Diploidy
DNA
DNA, Ribosomal - genetics
Evolution, Molecular
Evolutionary conservation
Fluorescence
Fluorescence in situ hybridization
Gene mapping
Gene sequencing
Genes
Genetic aspects
Genomes
Genomics
Histones
Histones - genetics
In Situ Hybridization, Fluorescence
Karyotype
Mammals
Multigene Family
Physical Chromosome Mapping
Physical mapping
Pleurodira
Podocnemididae
Podocnemis
Podocnemis expansa
Podocnemis unifilis
Reduction
Repetitive Sequences, Nucleic Acid
Reptiles & amphibians
Research and Analysis Methods
Ribosomal DNA
South American river turtle
Species Specificity
Synteny
Telomerase
Telomere - genetics
Testudines
Turtles
Turtles - classification
Turtles - genetics
Vertebrates
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Cytogenetic studies show that there is great karyotypic diversity in order Testudines (2n = 26-68), and that this may be mainly attributed to the presence/absence of microchromosomes. Members of the Podocnemididae family have the smallest diploid numbers of this order (2n = 26-28), which may be a derived condition of the group. Diverse studies suggest that repetitive-DNA-rich sites generally act as hotspots for double-strand breaks and chromosomal reorganization. In this context, we used fluorescent in situ hybridization (FISH) to map telomeric sequences (TTAGGG)n, 45S rDNA, and the genes encoding histones H1 and H3 in two species of genus Podocnemis. We also observed conservation of the 45S rDNA and H1 histone sequences (probable case of conserved synteny), but multiple conserved and non-conserved clusters of H3 genes, which colocalized with the interstitial telomeric sequences in the Podocnemis genome. Our results suggest that fusions have occurred between macro and microchromosomes or between microchromosomes, leading to the observed reduction in diploid number in the family Podocnemididae.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0197536