INTRODUCTION TO DNA

DNA, is an abbreviation of deoxyribonucleic acid, it is a complex organic chemical that is found in all living cells ie both prokaryotic and eukaryotic cells. The DNA molecule is the genetic information that transfers hereditary traits from parents to offspring's. The chemical DNA was first discovered in 1869, but its role in genetic inheritance was not demonstrated until in 1943. In 1953 James Watson and Francis Crick, determined the structure of the DNA is a double-helix polymer. The molecule contains instructions in the form of a genetic code for the development and functioning of the organism.

Most DNA is located in the cell nucleus where its called the nuclear DNA, but small amounts of DNA can also be found in the mitochondria where it is called mitochondrial DNA. The information in the DNA is stored as a code made up of four chemical bases ie; adenine(A),guanine(G), cytosine(C) and thymine(T). Human DNA consists of about 3billion bases and more than 99% of those bases are the same in all people. The order of these bases determines the information available for building and maintaining an organism similar to the way in which letters of the alphabet appear in a certain order to form words and sentences