1. Ch. 13.4: DNA Technology Applications
Objectives:
Describe the technique that enables scientists to mass-produce specific segments of DNA in a test tube.
Describe a technique used to compare DNA samples.
Vocabulary
PCR
Gel electrophoresis
Genetic Marker
DNA fingerprint

2. PCR Polymerase Chain Reaction
Technique used to MAKE COPIES of a SEGMENT OF DNA.
Start with 1 microgram DNA --> billions of copies
Need enough DNA to analyze.

3. PCR
Ingredients
PRIMERS (short strands of DNA that will pair w/ target sequence)
Nucleotides
DNA Polymerase

4. PCR Steps 1. Add heat to separate strands. 2. Cool & add primers
3. Primers bind to target strand.
4. DNA polymerase adds nucleotides.

5. Comparing DNA Gel Electrophoresis
Sorts molecules or fragments of DNA BY LENGTH.
Used to compare DNA fr. different people.

6. Gel Electrophoresis DNA is (-)charged.
DNA fragments move thru. gel to (+) end of gel bed.
Shorter fragments travel farthest.

7. PCR

8. DNA Fingerprinting
Pattern of DNA fragments produced by restriction enzymes.
Each person has unique patterns
Compare genetic markers between samples.
Genetic Markers =
Stretches of DNA that are variable among individuals.
Differences due to different alleles, mutations in intron sequences

9. Summary
PCR -->
Make copies of DNA from a drop of blood or hair follicle.
Gel electrophoresis -->
Separate fragments
DNA fingerprinting -->
Look for genetic markers to identify. Each person has unique DNA sequence = different fragments = diff. banding pattern (Fingerprint)