Aim: How can we analyze DNA?
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Transcript of Aim: How can we analyze DNA?
2006-2007 Regents Biology
Aim: How can we analyze DNA?
Do Now:
1. What are the advantages of selective breeding? Give an example.
Hw:
2006-2007 Regents Biology
Aim: How can we model the technique of gel electrophoresis?
Pre-Lab Questions
1. What happens to DNA prior to electrophoresis?
2.How is DNA separated in gel electrophoresis?
3. How are the bands DNA arranged in the gel?
Hw: Read pgs. 173-174 Answer Regents Practice B 12 on pg. 184, Part C 20 on pg. 185. Read pgs. 80 & 81 Define theory, fossil record, geologic time.
2006-2007 Regents Biology
BiotechnologyGel Electrophoresis
Regents Biology
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…
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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 gel electrophoresis
How does a gel work?
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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”
Regents Biology
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
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DNA
“swimming through Jello”
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Gel Electrophoresis
longer fragments
shorter fragments
powersource
completed gel
gel
DNA &restriction enzyme
wells
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Running a gel
1 2
cut DNA with restriction enzymes
fragments of DNAseparate out based
on size
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Stain DNA ethidium bromide
binds to DNA fluoresces under
UV light
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DNA fingerprint 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
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Allele 1GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTTCGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGAA
repeats
DNA patterns for DNA fingerprintscut sitescut sites
GCTTGTAACG GCCTCATCATCATCGCCG GCCTACGCTTCGAACATTGCCG GAGTAGTAGTAGCGGCCG GATGCGAA
1 2 3
DNA – +allele 1
Cut the DNA
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Person 1GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTTCGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGAA
Differences between peoplecut sitescut sites
DNA – +person 1
Person 2: more repeats
GCTTGTAACGGCCTCATCATCATCATCATCATCCGGCCTACGCTTCGAACATTGCCGGAGTAGTAGTAGTAGTAGTAGGCCGGATGCGAA
DNA fingerprint
person 2
1 2 3
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Uses: Evolutionary relationships Comparing DNA samples from different
organisms to measure evolutionary relationships
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DNA
1 32 4 5 1 2 3 4 5
turtle snake rat squirrel fruitfly
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Uses: Medical diagnostic Comparing normal allele to disease allele
chromosome with disease-causing
allele 2
chromosomewith normal
allele 1 –
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allele 1allele 2
DNA
Example: test for Huntington’s disease
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Uses: Forensics Comparing DNA sample from crime
scene with suspects & victim
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S1
DNA
S2 S3 V
suspects crime scene sample
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DNA fingerprints Comparing blood
samples on defendant’s clothing to determine if it belongs to victim DNA fingerprinting
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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 from
blood & from semen?RBC?
Regents Biology
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
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Uses: Paternity Who’s the father?
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DNA
childMom F1 F2–
2006-2007 Regents Biology
I’m a-glow!
Got any Questions?
2006-2007 Regents Biology
Biodiversity Lab
Which plant is most closely related to Botanus curus?
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Botanus curus Sequences
CAC GTG GAC TGA GGA CTC CTCDNA
GUG CAC CUG ACU CCU GAG GAGRNA
Val His Leu Thr Pro Glu GluAA
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Species X Sequences
CAC GTG GAC AGA GGA CAC CTCDNA
GUG CAC CUG UCU CCU GUG GAGRNA
Val His Leu Ser Pro Val GluAA
CAC GTG GAC TGA GGA CTC CTCBC
Val His Leu Thr Pro Glu GluBC
Regents Biology
Species Y Sequences
CAC GTG GAC AGA GGA CAC CTCDNA
GUG CAC CUG UCU CCU GUG GAGRNA
Val His Leu Ser Pro Val GluAA
CAC GTG GAC TGA GGA CTC CTCBC
Val His Leu Thr Pro Glu GluBC
Regents Biology
Species Z Sequences
CAC GTA GAC TGA GGA CTT CTCDNA
GUG CAU CUG ACU CCU GAA GAGRNA
Val His Leu Thr Pro Glu GluAA
CAC GTG GAC TGA GGA CTC CTCBC
Val His Leu Thr Pro Glu GluBC
Regents Biology
Amino Acid Sequences
Val His Leu Thr Pro Glu Glu
BC
X
Y
Z
Val His Leu Thr Pro Glu Glu
Val His Leu Ser Pro Val Glu
Val His Leu Ser Pro Val Glu