ABSTRACT
Simple in structure, bacteria reproduce by dividing in two to generate two identical cells. Bacteria need considerably fewer genes than complex human cells in order to survive; in fact, all 3,000 genes that they possess are carried on a single circular chromosome. Some bacteria possess a second, much smaller circular chromosome consisting of genes that are useful but not essential for survival. Hunters of human genes require many millions of copies of their gene of interest but of course human genes are on huge chromosomes inside their cells — not on plasmids inside bacteria. Establishing the sequence of a cloned gene and its mutated counterpart facilitates the development of a test to discover which version of the gene is present in cells from any given individual. A series of temperature changes is used to amplify the target and the entire process of gene amplification is completed within a few hours.
