genetic profiling, each indiviual is unique...

1. Presented By:
Aqsa Ayoub
Kinnaird college for
women lahore
GENETIC
FINGERPRINTING
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2. Introduction
• A technique used to distinguish between
individuals of the same species using only
samples of their DNA
• The process of DNA fingerprinting was
invented by Alec Jeffreys at the
University of Leicester in 1985.
• He was studying the gene of myoglobin.
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3. Genetic fingerprinting Process
Sampling
Blood
Hair
Saliva
Semen
Body tissue cells
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4. RESTRICTION FRAGMENT LENGTH
POLYMORPHISM
1. DNA EXTRACTION
• Cells are broken down to release DNA
2.DNA CUTTING
• The DNA is cut into fragments using
restriction enzymes.
• Each restriction enzyme cuts DNA at a
specific base sequence.
• The sections of DNA that are cut out are
called restriction fragments.
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5. Contd…….
3.FRAGMENTS SEPERATION
• Fragments are separated on
the basis of size using a process
called gel electrophoresis.
• DNA fragments are injected
into wells and an electric
current is applied along the
gel.
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6. Contd…..
• DNA is negatively charged so it is
attracted to the positive end of
the gel.
• The shorter DNA fragments move
faster than the longer fragments.
• DNA is separated on basis of size
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7. Contd…
4.DNA TRANSFER
• DNA split into single strands
using alkaline solution
• DNA fragments transferred from
gel to filter paper or nylon
membrane
• (This is called Southern blotting)
• Gel, with filter paper attached, is
removed & separated
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8. Contd….
5. ANALYSIS
Radioactive probe in solution
binds to DNA
Revealing a pattern of bands
X-ray film 8

9. PCR analysis
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10. Short Tandem Repeats (STR) analysis
• STR: repeated sequences of 3-5 base pairs (loci) which can be
identified in a known data base.
• Very useful in DNA analysis because they show great variability
among individuals.
• Newer and more precise method yielding errors of about 1 in 1029.
• Does not require very much DNA, can be coupled with PCR.
• Short tandem repeat (STR) technology : evaluates specific regions
(loci) that are found on DNA.
• The variable (polymorphic) nature of STR regions intensifies the
discrimination between one DNA profile and another. 10

11. CHANCES OF A MATCH
….there is a chance of 1 in 10 that this
fragment occurs in many individuals…
Suppose that…………
…and.there is a chance of 1 in 20 that this
fragment occurs in many individuals…
…and.there is a chance of 1 in 10 that this
fragment occurs in many individuals…
…and.there is a chance of 1 in 30 that this
fragment occurs in many individuals, but…
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12. Probability of a match
…the probability of all 4 bands matching in any person other than
the suspect is
1 in 10 x 1 in 20 x 1 in 10 x 1 in 30
= 1 in 10 x 20 x 10 x 30 That is 1 in 60,000
When a larger number of bands is involved, the probability that
the suspect is not guilty becomes one in many thousands*
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13. AmpFLP
• AmpFLP, or amplified fragment length polymorphism put
into practice during the early 1990s.
• This technique was also faster than RFLP analysis and used
PCR to amplify DNA samples.
• It relied on variable number tandem repeat (VNTR)
polymorphisms to distinguish various alleles,
• Which were separated on a polyacrylamide gel using an
allelic ladder (as opposed to a molecular weight ladder).
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14. Contd…
• Bands could be visualized by silver staining the gel.
• In addition, because the analysis is done on a gel, very high
number repeats may bunch together at the top of the gel,
making it difficult to resolve.
• AmpFLP analysis can be highly automated, and allows for
easy creation of phylogenetic trees based on comparing
individual samples of DNA.
• Due to its relatively low cost and ease of set-up and
operation, AmpFLP remains popular in lower income
countries.
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15. Applications
Forensic Science
Family Relationships
Health Care
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16. Thank you 
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