DNA FINGER PRINTING

DNA Finger Printing It is a genetic technique that takes over at the point where by conventional blood grouping leaves questions unanswered. It is based on the fact that each individual has an entirely unique genetic signature. It can be detected in body cells i.e. in blood, semen ,hair roots ,saliva ,flesh, bone marrow &etc. The technique involves isolation of DNA from a sample cell nucleus &injection into a gel. During electrophoresis in gel the DNA is separated into bands. The DNA band pattern in the gel is transferred to a nylon membrane by a technique called Southem blotting. Then exposed to controlled radioactivity. Then filter paper is placed over an X-ray plate & a distinctive pattern somewhat similar in nature to a Bar code emerges on development of X-ray.