Dna Fingerprinting And Forensic Applications

DNA FINGERPRINTING AND FORENSIC APPLICATIONS

DNA(DEOXYRIBONUCLEIC ACID)

DNA is a chemical structure that forms the genes.

DNA is a double helix, two strands of genetic material spiraled around each other.

Adenine, Guanine, Thymine ,Cytosine

WHAT IS DNA FINGERPRINTING ?

The chemical structure of everyone DNA is same but the difference lies in the base pairs

Using base pairs everyone can be solely identified but it is time consuming as there are millions of base pairs

Instead, scientists are able to use a shorter method, because of repeating patterns in DNA

They are able to determine whether two DNA samples are from the same person, related people, or non-related people.

PROCESS OF DNA FINGERPRINTING

It involves six steps1. The process begins with the cell or sample

from which the DNA is extracted.2. The DNA is cut into fragments using

restriction enzymes , The fragments are then separated into bands by electrophoresis through agarose gel .

3. The DNA band pattern is transferred into a nylon membrane .

ELECTROPHORESIS

CONT….

4. A radioactive DNA probe is introduced .The DNA probe binds to specific DNA sequences of the nylon membrane

5. The excess probe material is washed away leaving the unique DNA pattern

6. The radioactive DNA pattern is transferred to X-ray film by direct exposure .When developed the resultant visible pattern is DNA fingerprint.

DNA FINGERPRINTING PROCEDURESDAY ONE

DNA FINGERPRINTING PROCEDURESDAY TWO

DNA FINGERPRINTING PROCEDURESDAY THREE

Applications 1. Paternity and also

the Maternity .2. Criminal

identification and Forensics .

3. Personal identification.

Problems1. Generating a high

probability .2. Technical difficulties

FORENSIC DNA

DNA Sequences are compared to each other.

AGCTAGATCGTTATTCCGAG

AGCTAGATCGTTATTCCGAG

Hair found onSuspect

Victim

Conclusion: Hair may have come from the victim.

FORENSIC DNA (MITOCHONDRIA)

DNA Sequences are compared to each other.

AGCTAGATTGTTATTCCGAG

AGCTAGATCGTTATTCCGAG

Hair found onSuspect

Victim

Conclusion: Hair did not come from the victim

FORENSIC DNA

AGCTAGATTGTTATTCCGAG

AGCTAGATCGTTATTCCGAG

Blood butt at crime scene

Suspect #1

Conclusion: Blood could be from Suspects #2, #4 or other person with the same sequence.

AGCTAGATTGTTATTCCGAGSuspect #2

AGCTTGATTGTTATTCCGAGSuspect #3

AGCTAGATTGTTATTCCGAGSuspect #4

LET’S COMPARE…….bloodstain Satheesh Dheva John Ramalingam

DO WE HAVE A MATCH?bloodstain Satheesh Dheva John Ramalingam