Search results for "Nuclear DNA"
showing 10 items of 27 documents
Whole-genome analysis reveals contrasting relationships among nuclear and mitochondrial genomes between three sympatric bat species
2023
Understanding mechanisms involved in speciation can be challenging, especially when hybridization or introgression blurs species boundaries. In bats resolving relationships of some closely related groups has proven difficult due subtle interspecific variation both in morphometrics and molecular datasets. The endemic South American Histiotus bats, currently considered a sub-genus of Eptesicus, harbor unresolved phylogenetic relationships and of those is a trio consisting of two closely related species: Eptesicus (Histiotus) macrotus and E. (H.) montanus, and their relationship with a third, E. (H.) magellanicus. The three sympatric species bear marked resemblance to each other, but can be di…
Introgression of mitochondrial DNA among Myodes voles: consequences for energetics?
2011
Abstract Background Introgression of mitochondrial DNA (mtDNA) is among the most frequently described cases of reticulate evolution. The tendency of mtDNA to cross interspecific barriers is somewhat counter-intuitive considering the key function of enzymes that it encodes in the oxidative-phosphorylation process, which could give rise to hybrid dysfunction. How mtDNA reticulation affects the evolution of metabolic functions is, however, uncertain. Here we investigated how morpho-physiological traits vary in natural populations of a common rodent (the bank vole, Myodes glareolus) and whether this variation could be associated with mtDNA introgression. First, we confirmed that M. glareolus ha…
Reactive oxygen species derived from the mitochondrial respiratory chain are not responsible for the basal levels of oxidative base modifications obs…
2004
The mitochondrial electron transport chain (ETC) is the most important source of reactive oxygen species (ROS) in mammalian cells. To assess its relevance to the endogenous generation of oxidative DNA damage in the nucleus, we have compared the background (steady-state) levels of oxidative DNA base modifications sensitive to the repair glycosylase Fpg (mostly 7,8-dihydro-8-oxoguanine) in wild-type HeLa cells and HeLa rho0 cells. The latter are depleted of mitochondrial DNA and therefore are unable to produce ROS in the ETC. Although the levels of ROS measured by flow cytometry and redox-sensitive probes in rho0 cells were only 10-15% those of wild-type cells, steady-state levels of oxidativ…
An improved high yield method to obtain microsatellite genotypes from red deer antlers up to 200 years old.
2013
Analysis of DNA from older samples, such as museum specimen, is a promising approach to studying genetics of populations and ecological processes across several generations. Here, we present a method for extracting high quality nuclear DNA for microsatellite analysis from antlers of red deer (Cervus elaphus). The genotyping of individuals was based on nine microsatellite loci. Because the amount of DNA found in antlers was high, we could reduce the amount of sample and chemicals used and shorten the decalcification time in comparison to other methods. Using these methods, we obtained genotypes from antlers up to 200 years old.
CYTOGENETICS OF THE AMPHIPOD JASSA MARMORATA (COROPHIOIDEA: ISCHYROCERIDAE): KARYOTYPE MORPHOLOGY, CHROMOSOME BANDING, FLUORESCENTIN SITUHYBRIDIZATIO…
2000
Abstract Developing embryos proved to be a suitable source of cells for advanced cytological investigations on Amphipods. Conventional karyotyping, Ag- and fluorochrome-staining, C-banding, endonuclease digestion, fluorescent in situ hybridization (FISH) and nuclear DNA flow cytometric assay were tested in the Ischyroceridae Jassa marmorata. The karyotype consists of 6 chromosome pairs of which 5 are metacentric and 1 subtelocentric. The rDNA/FISH revealed that major ribosomal cistrons are located on the telomeric regions in the short arm of pair 6. A marked size variation of hybridization signals was observed. Silver and fluorochrome staining enhanced no chromosome regions. Constitutive he…
Living in isolation for almost 40 years: molecular divergence of the 28S rDNA and COI sequences between French and Polish populations of the cave bee…
2021
The paper gives the results of the first studies on the molecular divergence between native and non-native populations of Speonomus normandi hydrophilus (Jeannel, 1907). This species is endemic to Massif Arize in the Central Pyrenees (France), and represents highly specialised organisms that live underground. In 1982, one hundred specimens of S. normandi hydrophilus had been experimentally introduced into the Dzwonnica Cave (Poland). Since then, a numerous population has developed in the Towarna-Dzwonnica cave system, and the neighbouring Cabanowa Cave. After almost 40 years of isolation between native and non-native populations, the genetic variations were examined using the COI and 28S rD…
Fanconi's anaemia cells have normal steady-state levels and repair of oxidative DNA base modifications sensitive to Fpg protein
1998
Abstract Cells from Fanconi's anaemia (FA) patients are abnormally sensitive to oxygen. However, a distinct genetic defect in either the cellular defence against reactive oxygen species (ROS) or in their metabolic generation has not been identified to date. Recently, the gene for the human 8-hydroxyguanine (8-oxoG) glycosylase, which removes this oxidative base modification from the genome, has been localized on chromosome 3p25, i.e., in the same region as the FA complementation group D (FAD) gene. We therefore studied the removal of photosensitization-induced 8-oxoG residues from the DNA of FA cells, using Fpg protein, the bacterial 8-oxoG glycosylase, to quantify the lesions by alkaline e…
Nuclear DNA fractions with grossly different base ratios in the genome of the marine sponge Geodia cydonium
2008
The DNA of the marine sponge Geodia cydonium (G.c.), a member of the phylogenetically old phylum Porifera, was characterized by density gradient centrifugation and by determining its genetic complexity by reassociation kinetics. At least five subcomponents were identified by curve-fit analyses of analytical density gradient centrifugation profiles of total G.c.-DNA. Four of these subcomponents were isolated from total G.c.-DNA by preparative density gradient centrifugation. The GC-contents of the subcomponents were determined to be 36.4%, 44.0%, 58.7%, and 66.1%, respectively. To our knowledge, such an extreme heterogeneity of DNA composition has never before been observed for any organism.…
Base composition of DNA from glomalean fungi: high amounts of methylated cytosine.
1997
Glomales (Zygomycetes) are obligate fungal symbionts of roots of land plants and form arbuscular mycorrhiza. Sporal DNA of 10 isolates belonging to nine species was purified and the base composition was determined by RP-HPLC. Base composition fell in a narrow range between 30 and 35% G + C. A high amount of methylated cytosine (mC) accounting for 2-4% of the total nucleotides was found in all taxa. The DNA melting profile was defined for Scutellospora castanea. It corresponded to 32% G + C, and the shape of the denaturation curve suggested a heterogeneity in the GC content within the fungal genome. Knowledge of GC contents and variations between taxa are essential for evaluating nuclear DNA…
Photogenotoxicity of folic acid.
2013
Folic acid (FA), also named vitamin B9, is an essential cofactor for the synthesis of DNA bases and other biomolecules after bioactivation by dihydrofolate reductase (DHFR). FA is photoreactive and has been shown to generate DNA modifications when irradiated with UVA (360 nm) in the presence of DNA under cell-free conditions. To investigate the relevance of this reaction for cells and tissues, we irradiated three different cell lines (KB nasopharyngeal carcinoma cells, HaCaT keratinocytes, and a melanoma cell line) in the presence of FA and quantified cytotoxicity and DNA damage generation. The results indicate that FA is phototoxic and photogenotoxic by two different mechanisms. First, ext…