Point mutations might initiate very dangerous changes in human bodies. One of the most dangerous affects is cancer. Cancers arise from the buildup of multiple mutations in genes regulating cellular growth and differentiation. Identification of such mutations in numerous genes represents a significant challenge in genetic analysis, particularly when the majority of DNA in a tumor sample is from wild-type stroma. Due to their subtle nature, the point mutations are the most difficult to detect of all the genetic alterations.
Mutations are detected and localized by the presence and size of the RNA fragments generated by cleavage at the mismatches.
The single strand conformation polymorphism is another method. It consist of detection of polymorphisms of human DNA by gel electrophoresis as single-strand conformation polymorphisms. It is based on the differences in the secondary structure of single-strand DNA molecules differing in a single nucleotide, which also is frequently reflected in an alteration of their electrophoretic mobility in nondenaturing gel electrophoresis.
In denaturing gradient gel electrophoresis, the double stranded DNA is subjected to electrophoresis in gel that has an increasing concentration of denaturant along the length of the gel. It works by separation of random fragments of DNA according to properties of their sequences. The fragment melts while traveling through the gel. The melting proceeds in segments, called melting domains, because of the cooperative nature of the denaturation of the