ABSTRACT
The genetic material, DNA (deoxyribonucleic acid), in the cell nucleus holds the code that dictates the amino acid sequence of all proteins in the body. A small amount of DNA is also found in the mitochondria (mtDNA). Should there be a change in the sequence of the nucleotides, which comprise DNA and that change in code results in a change in the amino acid used in the synthesis of the gene product, then the sequence of amino acids in the resultant protein could be different. This change in the normal sequence of bases in the DNA is called mutation. It can be either a spontaneous mutation or one induced by drugs or a virus or any one of a number of external variants that target the genetic material of the cell. Some changes in the base sequence have no effect on the amino acid used for protein synthesis. This is because many of the amino acids have more than one code in the DNA. When such a base substitution occurs, it is a polymorphism, not a mutation. Polymorphisms also occur in the noncoding regions of the DNA and in sections of the DNA that have no relevance when it comes to the function of the gene product.
