The DNA profiling of each individual is unique because of the diverse in polymorphic regions present in genome of every individual. These polymorphic regions used for identification are the non-coding regions of the genome. The polymorphic regions of the DNA do not code for proteins and which make-up 95% of our genetic DNA. Hence these regions are therefore called the "junk DNA". Although these "junk DNA" regions do not code for proteins, they are involved in regulating gene expression, they help in reading of other genes that code for protein and are a large portion of the chromosome structure. The junk DNA regions are made-up of length polymorphisms, which show variations in the physical length of the DNA molecule. In DNA profile the length of the polymorphisms in the non-coding areas is measured as it varies with each individual. These polymorphisms are identical repeat sequences that are present in non- coding DNA region. At specific loci on the chromosome the number of tandem repeats varies between individuals. There will be a certain number of repeats for any specific loci on the chromosome. Depending on the size of the repeat , the repeat regions are classified into two groups. Short tandem repeats (STRs) contain 2-5 base pair repeats and variable number of tandem repeats (VNTRs) have repeats of 9-80 base pairs.