Technology
A molecular cytogenetic method combining chromosomal comparative genomic hybridization technique and microarray to detect chromosomal aberrations and changes in DNA copy numbers in the genome, using oligonucleotides immobilized on a solid support as targets for hybridization.
Diagnostic Methods
Technology
A molecular genetic technique that isolates and sequences chromosomal regions that are rich in open chromatin. First, nuclei are harvested from a cellular sample. Then a hyperactive Tn5 transposase is added to the nuclei where it excises non-nucleosomal DNA strands and ligates co-administered high-throughput sequencing adapters (tagmentation). The tagged DNA fragments are isolated, amplified by PCR and sequenced. The number of reads for specific region of DNA correlate with increased chromatin accessibility and this method can identify regions of transcription factor and nucleosome binding.
Diagnostic Methods
Product
Sample Preparation
Technology
A DNA sequencing technique that can differentiate cytosine from 5-methylcytosine in a DNA sample. First, a denatured DNA sample is treated with bisulfite which converts non-methylated cytosine to uracil. Next, the sample is amplified using a PCR method that does not discriminate between non-methylated and methylated sequences. The amplified DNA is subjected to nucleotide sequencing. The resulting sequence is compared to an identical control sample of DNA that was not treated with bisulfite. Unmethylated cytosines will be displayed as cytosines in the control sample and as thymines in the bisulfite-treated sample.
Diagnostic Methods
Technology
A molecular genetic technique that combines chromatin immunoprecipitation (ChIP) with massively parallel DNA sequencing to map the binding sites of DNA-associated proteins in a sample of cells. First, crosslinked protein-DNA complexes are isolated using ChIP. Next, the crosslinks are broken, the proteins are removed and the purified DNA is modified with adaptor oligonucleotides to facilitate massively parallel DNA sequencing. Following sequencing, the DNA sequences that are obtained can be mapped to their genomic locations.
Diagnostic Methods
Technology
A technique that utilizes immunoprecipitation to find protein-DNA interactions in a biological sample. First, the sample is treated causing the formation of protein-chromatin crosslinks. Then, the sample is sheared to separate individual protein-DNA complexes. Finally, an antibody directed against a protein of interest is applied and the protein-DNA complexes are immunoprecipitated.
Diagnostic Methods
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Sample Preparation
Technology
Comparative genomic hybridization (CGH) is a technique that allows the detection of losses and gains in DNA copy number across the entire genome without prior knowledge of specific chromosomal abnormalities. Comparative genomic hybridization utilizes the hybridization of differentially labeled tumor and reference DNA to generate a map of DNA copy number changes in tumor genomes. Comparative genomic hybridization is an ideal tool for analyzing chromosomal imbalances in archived tumor material and for examining possible correlations between these findings and tumor phenotypes. (from Ried et al. J Mol Med 1997 75:801-14)
Diagnostic Methods
Technology
A DNA sequencing technique in which a mixture of deoxynucleosidetriphosphates (dNTPs) and chain-terminating dNTPs, which are radioactively or fluorescently labeled, are combined within the reaction mixture. Once the reaction is complete, the DNA strands are separated by size, and the labeled chain terminating dNTPs can be read in sequence by the investigator or by a machine.
Diagnostic Methods
Technology
Identification of an individual's genetic information from their DNA.
Diagnostic Methods
Technology
Any method that extracts and purifies DNA from biological samples, which can include the proper handling of biological samples prior to nucleic acid isolation, the separation of DNA from the rest of the components in the samples, and the storage of the DNA isolates.
Diagnostic Methods
Technology
The determination of the sequence of purines and pyrimidines in deoxyribonucleic acid (DNA).
Diagnostic Methods