This document provides an overview of DNA fingerprinting. It begins by defining DNA fingerprinting as a forensic technique used to identify individuals based on characteristics of their DNA. It then describes the principle behind DNA fingerprinting, which is that variable numbers of tandem repeats in DNA vary between individuals. The methodology section outlines the 5 main steps: 1) DNA extraction, 2) DNA cutting using restriction enzymes, 3) gel electrophoresis to separate DNA fragments by length, 4) Southern hybridization to transfer DNA to a membrane, and 5) autoradiography to produce fingerprints. Applications discussed include individuality testing, paternity/maternity disputes, identifying hereditary diseases, and forensics.

1. DNA FINGERPRINTING
P.SUNDHARAMOORTHY
I MSc BIOTECHNOLOGY
A10PBT011

2. Index
Introduction
Principle
Methodology
Applications
Reference

3. What is DNA
Fingerprinting?
• DNA Fingerprinting is a forensic
technique used to identify individuals by
characteristics of their DNA.
• The process of DNA fingerprinting was
invented by Alec Jeffrey at the
University of Leicester in 1985.
• Also called DNA Profiling or
Molecular Fingerprinting.

4. PRINCIPLE
Variable Number of Tendem Repeats
{VNTR}
•Small part of DNA
vary from individual
to individual
•Chances 30,000
million to 1 (except
for identical twins).

5. Methodology
Steps involved :-
1. DNA Extraction
2. DNA Cutting
3. Gel Electrophoresis
4. Southern Hybridization
5. Autoradiography

6. •Cells are broken
down to release
DNA.
•Sample Collect
from:-
Blood
Hair
Saliva
Semen
Body tissue cells
1. DNA EXTRACTION

7. 2. DNA CUTTING
• The DNA is cut into fragments
using
restriction enzymes.
• Each restriction enzyme cuts DNA
at a specific base sequence.

8. 3.Gel Electrophoresis
• Fragments separated by
length
• DNA (negatively charged)
• Moves towards +ve
terminal
• Shorter fragments move
faster

9. 4. Southern Hybridization
• DNA fragments
transferred from
gel to filter paper or
nylon membrane
• DNA is split into
single strands
using an alkaline
solution
•Radioactive probe in
solution binds to DNA

10. 5.Autoradiography
• X-ray film placed over filter paper.
• Radioactivity probes
makes dark
spots on film.
DNAFingerprinting
patterns

11. Example
• Violent murder case
• The forensics team retrieved a
blood sample from the crime
scene.
• They prepared DNA profiles of the blood
sample, the victim and a suspect as
follows:

12. DNA Profile
V victim
S sample from
crime scene
S1 suspect 1
S2 suspect 2
S3 suspect 3
V S S
1
S
2
S
3

13. Paternity test
1 mother
2 son
3possible fatherA
4 possible father B
There is a match between
one of the child’s restriction
Fragments and one of the
mother’s.
1 2 3 4

14. Applications
• Individuality
• Paternity/Maternity
Disputes
• Hereditary Diseases
• Forensics
• Sociology

15. REFERENCES
B.D.Singh, Kalyani publishers,
Biotechnology Expanding Horizons, Third
edition, chapter 13, Biotechnology and
Health Care, pg no. 565-574.
V. Kumaresean, Saras publication,
Biotechnology, Sixth edition, chapter 25, DNA
Fingerprinting, pg no. 306-313.
 http://www.google.com
 http://www.wikipedia.com

16. .
Thank you