Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Among human being, 99.9 percent of base sequence is the same, yet there is a difference in the DNA sequences of any two individuals. The difference in these sequences of DNA make every individuals unique in their phenotypic appearance. The difference in these sequences of DNA can easily be determined by fingerprinting. If one aims to find out genetic differences between two individuals or among individuals of a population, DNA fingerprinting is a very quick way to compare the DNA sequences of these individuals.
In DNA fingerprinting, differences existed in some specific regions/of DNA sequences are identified that are known as Satellite DNA. In DNA fingerprinting. the differences of this satellite DNA is determined. The satellite DNA contains small stretches of base pairs repeated many times, it is therefore, also called repetitive DNA. These repetitive DNA can easily be separated from bulk of genomic DNA by caesium chloride density ultra-centrifugation method in the form of bands. The major peaks are obtained for bulk DNA and lower peaks for satellite/repetitive DNA. This technique was developed by Alec Jeffrey. This technique needs the use of DNA probe. Alec Jeffrey used satellite DNA as probe-as it shows very high degree of polymorphism.
Applications: This technique is now used to:
(1) Identify the criminals in forensic laboratories.
(2) Determine paternity, that is, who the true biological father or mother is of a child.
(3) Verify whether a hopeful immigrant is, as, he or she claims, really a close relative of already an established resident.
(4) identify racial groups to rewrite biological evolution.