‘‘A very small sample of tissue or even a drop of blood can help determine paternity.’’ Provide a scientific explanation to substantiate how it is possible.

• DNA fingerprinting the technique by which the comparison of the DNA sequences of any two individuals done.

• A polymorphism in a DNA sequence is the basis of genetic mapping of the human genome as well as DNA fingerprinting.

• DNA fingerprinting involves identification of differences in some specific regions in DNA sequence called as repetitive DNA because, in these sequences, a small stretch of DNA is repeated many times.

• These sequences show the high degree of polymorphism and form the basis of DNA fingerprinting.

• Since from an individual, DNA from every tissue (such as blood, hair-follicle, skin, bone, saliva, sperm, etc.), show the same degree of polymorphism, therefore they are very useful identification tools in forensic applications.

• DNA fingerprinting is the base of paternity testing because the polymorphisms are inheritable from parents to children.

• In the case of disputes, a very small sample of tissue or even a drop of blood can help determine paternity.