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LAY OUT 3 YARN PIECES ON YOUR DESK
DON’T STRETCH !
TRIM ALL YOUR YARN PIECES SO THEY ARE THE SAME LENGTH- 50 cm
Image from : http://thecreativeimperative.blogspot.com/2011/06/american-flag-wreath-sort-of.html
RESTRICTION ENDONUCLEASES
Use the “restriction enzymes” provided to:
Cut one piece of yarn with EcoRI –Cuts at 8 cm AND 22 cm
Cut one piece of yarn with HindIII– Cuts at 18 cm AND 35 cm
Cut one piece of yarn with BOTH EcoRI AND HindIII
SET UP YOUR DESKTOP AS A GEL
+
DNA
–
EcoRI +HindIIIEcoRI HindIII
Use sticky notes to LABEL THE + and – poles
Use sticky notes to LABEL your lanes
Load your “gel” withyour “DNA” that has been cut with“restriction enzymes”
Complete RFLP analysis and draw a picture of the results in your BILL
EXPLAIN WHY DNA moves in an electric field toward the POSITIVE pole.
EXPLAIN the relationship between FRAGMENT SIZE and DISTANCE MOVED on a gel.
Linus Pauling used RFLP analysis to show that the sickle cell mutation caused a change in the DNA code. He cut the gene from a person with normal hemoglobin and a person with sickle cell anemia with a restriction enzyme and compared them using RFLP analysis.
Use what you know about the sickle cell mutation to EXPLAIN why the gel patterns in these people might show different numbers and lengths of fragments on a gel.
SP 6: The student can work with scientific explanations and theories.6.2 The student can construct explanations of phenomena based on evidence produced through scientific practices
http://image.slidesharecdn.com/4-140318210158-phpapp01/95/biotechnology-4-61-638.jpg?cb=1395195168
http://image.slidesharecdn.com/4-140318210158-phpapp01/95/biotechnology-4-61-638.jpg?cb=1395195168
MAKE A PREDICTION about what the gel pattern from a person who is heterozygous for the sickle cellallele might look like
SP 6: The student can work with scientific explanations and theories.6.1 The student can make claims and predictions about natural phenomena based on scientific theories and models.
What if instead of using different restriction enzymes on same DNA you used the SAME restriction enzyme on DNA from DIFFERENT people?
Give at least FOUR (4) examples of what could this be used for.
?????????
2007-2008
More Basic Biotechnology ToolsSorting & Copying DNA
Modified from a slide show by Kim Foglia
Many uses of restriction enzymes…• Now that we can cut DNA with restriction
enzymes…– we can cut up DNA from different people… or
different organisms… and compare it
– why?• forensics• medical diagnostics• paternity• evolutionary relationships • and more…
Comparing cut up DNA• How do we compare DNA fragments?– separate fragments by size
• How do we separate DNA fragments?– run it through a gelatin• agarose• made from algae
– gel electrophoresis
Gel electrophoresis• A method of separating DNA in
a gelatin-like material using an electrical field– DNA is negatively charged– when it’s in an electrical field it
moves toward the positive side
+–
DNA
“swimming through Jello”
• DNA moves in an electrical field…– so how does that help you compare DNA
fragments?• size of DNA fragment affects how far it travels– small pieces travel farther– large pieces travel slower & lag behind
Gel electrophoresis
+–
DNA
“swimming through Jello”
Gel Electrophoresis
longer fragments
shorter fragments
powersource
completed gel
gel
DNA &restriction enzyme
wells
-
+
Running a gel
1 2
cut DNA with restriction enzymes
fragments of DNAseparate out based on size
3
Stain DNA– ethidium bromide
binds to DNA– fluoresces under UV
light
Uses: Evolutionary relationships• Comparing DNA samples from different
organisms to measure evolutionary relationships
–
+
DNA
1 32 4 5 1 2 3 4 5
turtle snake rat squirrel fruitfly
Uses: Medical diagnostic• Comparing normal allele to disease allele
chromosome with disease-causing allele 2
chromosomewith normal allele 1 –
+
allele 1allele 2
DNA
Example: test for Huntington’s disease
Uses: Forensics• Comparing DNA sample from crime scene
with suspects & victim
–
+
S1
DNA
S2 S3 V
suspects crime scene sample
DNA fingerprints• Comparing blood
samples on defendant’s clothing to determine if it belongs to victim– DNA fingerprinting– comparing DNA banding
pattern between different individuals
– ~unique patterns
Differences at the DNA level• Why is each person’s DNA pattern different?– sections of “junk” DNA• doesn’t code for proteins• made up of repeated patterns
– CAT, GCC, and others– each person may have different number of repeats
• many sites on our 23 chromosomes with different repeat patterns
GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTTCGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGAA
GCTTGTAACGGCATCATCATCATCATCATCCGGCCTACGCTTCGAACATTGCCGTAGTAGTAGTAGTAGTAGGCCGGATGCGAA
Allele 1GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTTCGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGAA
repeats
DNA patterns for DNA fingerprintscut sitescut sites
GCTTGTAACG GCCTCATCATCATCGCCG GCCTACGCTTCGAACATTGCCG GAGTAGTAGTAGCGGCCG GATGCGAA
1 2 3
DNA – +allele 1
Cut the DNA
Allele 1GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTTCGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGAA
Differences between peoplecut sitescut sites
DNA – +allele 1
Allele 2: more repeatsGCTTGTAACGGCCTCATCATCATCATCATCATCCGGCCTACCGAACATTGCCGGAGTAGTAGTAGTAGTAGTAGGCCGG
DNA fingerprint
allele 2
1 2 3
RFLPs• Restriction Fragment Length Polymorphism– differences in DNA between individuals
change in DNA sequence affects restriction enzyme “cut” site
creates different fragment sizes & different band pattern
Alec Jeffries 1984
RFLP / electrophoresis use in forensics• 1st case successfully using DNA evidence– 1987 rape case convicting Tommie Lee Andrews
“standard”
“standard”
“standard”
“standard”
semen sample from rapist
semen sample from rapist
blood sample from suspect
blood sample from suspect
How can you compare DNA fromblood & from semen?RBC?
Electrophoresis use in forensics• Evidence from murder trial– Do you think suspect is guilty?
“standard”
blood sample 3 from crime scene
“standard”
blood sample 1 from crime scene
blood sample 2 from crime scene
blood sample from victim 2
blood sample from victim 1
blood sample from suspect OJ Simpson
N Brown
R Goldman
Uses: Paternity • Who’s the father?
+
DNA
childMom F1 F2–