Its no accident that off-spring resemble their parents. Deoxyribonucleic acid or DNA, located within each cell nucleus is a special chemical, that determines our genetic inheritance in a very orderly way. Under the microscope DNA looks like a mass of tangled threads which consist of tiny subunits called genes. Genes carry instructions, sometimes called the blueprint of life, for various characters like hair color, height, eye color. Our genes are received from both mother and father, half from each.
Genes instruct our bodies to make proteins - which determines the shape and function of each cell.
Each gene controls the production of a particular protein. Its major aims are to map and determine the chemical sequences of the three billion nucleotide base pairs that comprise the human genome. Completion of the HGP in the projected 15 years will provide a source book for biology and medicine. There are many different techniques involved in gene screening. With the start of the Human Genome Mapping Project some of these techniques have been altered to speed up the screening process.