TOWARDS ANALYSING COMPARATIVE GENOMIC HYBRIDISATION METHOD

Abstract

Human DNA has 6 million nucleotides packaged into 2 sets of Chromosomes. Mutations can change the sequence of nucleotides. Mutations can be defined as any change in the DNA sequence of a cell. Mutations may be caused by exposure of DNA to DNA damaging agents in the environment like ultraviolet rays, chemical carcinogens (eg: aflatoxin) etc., or by mistakes during cell divisions. COPY - NUMBER VARIATIONS (CNVs) are alterations of a genome that results in the cell having an abnormal number of copies of one or more sections of the DNA. The molecular - cytogenetic method for the analysis of copy number changes in the DNA content of a given subject’s DNA and often in tumor cells is known as comparative genomic hybridization. Comparative genomic hybridisation is used for studying chromosomal changes in cancer. In human pathology, analysis of genetic abnormalities which causes tumours and cancers is increasingly important. Many techniques are available to fulfill this purpose such as DNA cytometry, tumor cytogenetics, fluorescence in situ hybridization (FISH) and microsatellite assay. But all these techniques have certain advantages and disadvantages. They may be sometime expensive (DNA cytometry) and more laborious. So, the scientists developed a molecular cytogenetic technique called comparative genomic hybridization.