DNA Identification

1
DNA Identification

• Where does DNA come from?
• 1/2 from mom
• 1/2 from dad
• What is it?
• Blue print of life
• How is DNA different among us?
• Common vs Different
• What does DNA mean?
• Deoxyribonucleic Acid

2
Where can DNA be found?
Cell Types
Blood
Hair Roots
Saliva
SAME
Sweat
Semen
Various Tissue
3
Types of objects where DNA may be found

• Blood Stains
• Semen Stains
• Chewing Gum
• Stamps Envelopes
• Penile Swabs

• Sweaty Clothing
• Bone
• Hair
• Fingernail Scrapings
• Saliva

4
Where is DNA in the body?
Cell
5
Where types of DNA are found in a cell?
Mitochondrial DNA
Nuclear DNA
6
Where is DNA in the body?
7
Where is DNA in the body?
8
DNA- What it looks like
Units
A Adenine
T Thymine
G Guanine
C Cytosine
9
STR
Short Tandem Repeat
AGAT
DNA Profile 4,6
TCTA
DNA Profile 5,7
10
Isolation of DNA
Chemical
DNA
Blood Hair Roots Saliva Sweat Tissue
11
Differential Isolation of DNA
Semen stain
Remove Epithelial DNA
Sperm DNA
12
Amplification
(making copies)
Solution
13
DENATURE
Step one of a single cycle
14
ANNEAL
Step two of a single cycle
15
EXTEND
Step three of a single cycle
16
Amplification
PCR (Polymerase Chain Reaction)
17
Analysis of amplified DNA
DNA Profile
18
(No Transcript)
19
15,16
16,17
20,23
12,14
30,30
X,Y
13.2,15
20
STR results

• The DNA from the evidence stain and the
  reference sample from the suspect match.

The frequency of this matching pattern is
approximately 1 in 520,000,000,000 in the
Caucasian population, 1 in 618,500,000,000 in the
African American population and 1 in
532,000,000,000 in the Hispanic population.
Based on these results the suspect is the source
of the evidence stain to a reasonable degree of
scientific certainty.