Gene bank or genomic library is a complete collection of cloned DNA fragments which comprises the entire genome of an organism of an organism. Probes with DNA sequence complementary to the gene to be isolated are used. They bind with the desired gene making it visible and help in isolating it from the library. Cloning vectors are utilized to insert foreign DNA into another cell and create multiple copies of the same. A restriction enzyme is an enzyme that cleaves DNA into fragments at or near specific recognition sites within molecules. Related Theory In order to analyse a Southern Blot, a radioactive genetic probe is used in a hybridisation reaction with the DNA. If an X-ray is taken of the Southern Blot after a radioactive probe has been allowed to bind with the denatured DNA on the paper: only the areas where the radioactive probe binds will show themselves on the film (autoradiography). This allow researchers to identify, in a particular person's DNA, the occurrence and frequency of the particular genetic pattern contained in the probe.