Plus Two Biology|Zoology|Chapter-6|Molecular Basis of Inheritance in Malayalam|Part-VIII|DNA Fingerprinting

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In this session Bio Strips Media takes through the important topics of Molecular Basis of Inheritance. It is one of the most important and scoring topics in Plus Two Biology Exam and NEET Exam. 

 

This lecture covers:

·         DNA Fingerprinting

·         Principle

·         Procedure

·         Applications

 

 

The content being discussed in this video will be helpful for those appearing for the Plus Two Biology Exam and NEET Biology Exam.

DNA FINGER PRINTING

·        The technique of DNA fingerprinting was developed by Dr.Alec Jefrey.

·        The process is also known as DNA Typing or DNA Profiling.

·        The most important fact for DNA fingerprinting are the short nucleotide repeats, called Variable Number Tandem Repeats (VNTRs), that vary in number from person to person and inherited.

·        The VNTRs of two persons may be of same length and sequence at certain sites, but vary at others.

·        The procedure of DNA fingerprinting includes the following major steps:

·        Extraction – DNA is extracted from the cells in a high speed, refrigerated centrifuge.

·        Amplification – many copies of the extracted DNA are made by polymerase chain reaction (PCR).

·        Restriction Digestion – DNA is cut into fragments with restriction enzymes into precise reproducible sequences.

·        Separation of DNA sequences or restriction fragments – the cut DNA fragments are introduced and passed through electrophoresis set up containing agarose polymer gel, the separated fragments can be visualized by staining them with a dye that shows fluorescence under UV radiation.

·        Southern Blotting – The separated DNA sequences are transferred on to a nitrocellulose or nylon membrane or sheet placed over the gel.

·        Hybridization – The nylon membrane is immersed in a bath and radioactive probes (DNA segments of known sequence) are added, these probes target a specific nucleotide sequence that is complementary to them.

·        Autoradiography – The nylon membrane is pressed on to an X-ray film and dark bands develop at the probe sites which resemble the bar codes.

·        DNA fingerprinting technique is used for following purposes:

·        To identify criminals in the forensic laboratories.

·        To determine the real parents in case of disputes.

·        To identify racial groups to rewrite the biological evolution.