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The comet assay (single-cell gel electrophoresis) is a simple method for measuring deoxyribonucleic acid (DNA) strand breaks in eukaryotic cells. Cells embedded in agarose on a microscope slide are lysed with detergent and high salt to form nucleoids containing supercoiled loops of DNA linked to the nuclear matrix. Electrophoresis at high pH results in(More)
The endogenous production of oxidative damage in DNA by free radicals released as a by-product of respiration is a likely cause of mutations which, if they occur in appropriate genes, may lead to cancer. Using an endonuclease specific for oxidized pyrimidines, in conjunction with the highly sensitive method of single cell gel electrophoresis, we have(More)
The extent of linkage disequilibrium (LD) within a population determines the number of markers that will be required for successful association mapping and marker-assisted selection. Most studies on LD in cattle reported to date are based on microsatellite markers or small numbers of single nucleotide polymorphisms (SNPs) covering one or only a few(More)
As part of the Fourth International Workshop on Genotoxicity Testing (IWGT), held 9-10 September 2005 in San Francisco, California, an expert working group on the Comet assay was convened to review and discuss some of the procedures and methods recommended in previous documents. Particular attention was directed at the in vivo rodent, alkaline (pH >13)(More)
The comet assay (single-cell gel electrophoresis), which measures DNA strand breaks at the level of single cells, is very easily applied to human lymphocytes, and therefore lends itself to human biomonitoring studies. For the examination of DNA base oxidation (a specific marker of oxidative damage), the assay is modified by including a stage at which the(More)
A range of applications of the alkaline comet assay is covered, from investigations of the physicochemical behaviour of DNA, through studies of cellular responses to DNA damage, to biomonitoring of human populations. The underlying principles of this assay are discussed, and new evidence presented which supports the concept of relaxation of supercoiled(More)
Single cell gel electrophoresis is a sensitive method for detecting DNA strand breaks. Cells embedded in agarose are converted to nucleoids by treating with detergent and high salt. DNA breaks render the nucleoid DNA susceptible to extension by electrophoresis, forming 'comets'. We find that when DNA breakage resulting from H2O2 treatment is examined,(More)
Analysis of single nucleotide polymorphisms (SNPs) has been and will be increasingly utilized in various genetic disciplines, particularly in studying genetic determinants of complex diseases. Such studies will be facilitated by rapid, simple, low cost and high throughput methodologies for SNP genotyping. One such method is reported here, named tetra-primer(More)
There is a need for a reliable, robust and sensitive assay for DNA repair, suitable for use with human lymphocyte samples in molecular epidemiological investigations. The comet assay (single cell alkaline gel electrophoresis) has been modified to measure the ability of a simple subcellular extract of lymphocytes to carry out the initial step of repair, i.e.(More)
Oxidized bases in DNA can be measured directly by high-performance liquid chromatography (HPLC). 7,8-Dihydro-8-oxo-guanine (8-OHgua), as the most abundant oxidation product, is often regarded as an indicator of oxidative stress. Estimates of endogenous 8-OHgua levels in human lymphocyte DNA are between 2 and 8 for every 10(5) unaltered bases--a high(More)