Ch. 13.4: DNA Technology ApplicationsObjectives:

1. Describe the technique that enables scientists to mass-produce specific segments of DNA in a test tube.

2. Describe a technique used to compare DNA samples.

Vocabulary PCR Gel

electrophoresis Genetic Marker DNA fingerprint

PCRPolymerase Chain

ReactionTechnique used to

MAKE COPIES of a SEGMENT OF DNA.

Start with 1 microgram DNA --> billions of copies

Need enough DNA to analyze.

PCRIngredients PRIMERS (short strands

of DNA that will pair w/ target sequence)

Nucleotides

DNA Polymerase

PCRSteps1. Add heat to separate

strands.2. Cool & add primers3. Primers bind to target

strand.4. DNA polymerase adds

nucleotides.

Comparing DNAGel ElectrophoresisSorts molecules or fragments of DNA BY LENGTH. Used to compare DNA fr. different people.

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

PCR

Genetic Markers = Stretches of DNA that are variable among individuals.Differences due to different alleles, mutations in intron sequences

DNA Fingerprinting Pattern of DNA

fragments produced by restriction enzymes.

Each person has unique patterns

Compare genetic markers between samples.

SummaryPCR --> 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)