NEET Botany Molecular Basis of Inheritance Questions Solved

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Following a severe accident, many charred-disfigured bodies are recovered from 

the site making the identification of the dead very difficult. Name and explain 

the technique that would help the authorities to establish the identity of the dead

to be able to hand over the dead to their respective relatives.

The technique that would help establish the identity of the dead is DNA fingerprinting.

DNA polymorphism is the basis of DNA fingerprinting. In some specific regions a small

stretch of DNA is repeated many times known as repetitive DNA. They do not code for

any proteins but they form a large portion of human genome. These sequences show

high degree of polymorphism. Since DNA from every tissue such as blood, hair-follicle,

skin, bone, saliva, sperm etc. show the same degree of polymorphism, they become very

useful identification tools in forensic applications.

DNA fingerprinting technique:

(i) Isolation of DNA.

(ii) Digestion of DNA by restriction endonucleases.

(iii) Separation of DNA fragments by gel electrophoresis. VNTRs are multiplied

by PCR technique if required.

(iv) Transferring (blotting) of separated DNA fragments of synthetic membranes, such

as nitrocellulose or nylon.

(v) Hybridisation using labelled VNTR probe.

(vi) Detectation of hybridised DNA fragments by auto radiography.

(vii) The autoradiogram gives bands of differing sizes. These band gives a characteristic

pattern for an individual DNA. It differs from individual to individual in a population 

except in the case of monozygotic (identical) twins.

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