Biotechnology Gel Electrophoresis Regents Biology 2006 2007 Many
Biotechnology Gel Electrophoresis Regents Biology 2006 -2007
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 u why? u § § § Regents Biology forensics medical diagnostics paternity evolutionary relationships and more…
Comparing cut up DNA § How do we compare DNA fragments? u separate fragments by size § How do we separate DNA fragments? run it through a gelatin u gel electrophoresis u § How does a gel work? Regents Biology
Gel electrophoresis § A method of separating DNA in a gelatin-like material using an electrical field DNA is negatively charged u when it’s in an electrical field it moves toward the positive side u DNA – Regents Biology “swimming through Jello” +
Gel electrophoresis § DNA moves in an electrical field… u so how does that help you compare DNA fragments? § size of DNA fragment affects how far it travels w small pieces travel farther w large pieces travel slower & lag behind DNA – Regents Biology “swimming through Jello” +
Gel Electrophoresis DNA & restriction enzyme longer fragments wells power source gel Regents Biology + shorter fragments completed gel
fragments of DNA separate out based on size Running a gel cut DNA with restriction enzymes 1 2 Stain DNA u u Regents Biology ethidium bromide binds to DNA fluoresces under UV light 3
DNA fingerprint § Why is each person’s DNA pattern different? u sections of “junk” DNA § doesn’t code for proteins § made up of repeated patterns w CAT, GCC, and others w each person may have different number of repeats § many sites on our 23 chromosomes with different repeat patterns GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTT CGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGA A GCTTGTAACGGCATCATCATCCGGCCTACG CTT Regents Biology CGAACATTGCCGTAGTAGTAGGCCGGATGC GAA
DNA patterns for DNA fingerprints Allele 1 cut sites repeats cut sites GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTT CGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGA A Cut the DNA GCTTGTAACG GCCTCATCATCATCGCCG GCCTACGCTT CGAACATTGCCG GAGTAGTAGTAGCGGCCG GATGCGAA 1 2 – DNA allele 1 Regents Biology 3 +
Differences between people Person 1 cut sites GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTT CGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGA A Person 2: more repeats GCTTGTAACGGCCTCATCATCATCCGGCCT ACGCTT CGAACATTGCCGGAGTAGTAGTAGGCCGG ATGCGAA 1 2 DNA fingerprint – DNA person 1 person 2 Regents Biology 3 +
Uses: Evolutionary relationships § Comparing DNA samples from different organisms to measure evolutionary relationships turtle snake rat squirrel fruitfly – DNA 1 + Regents Biology 2 3 4 5 1 2 3 4 5
Uses: Medical diagnostic § Comparing normal allele to disease allele chromosome with normal allele 1 chromosome with disease-causing allele 2 all ele 1 all ele 2 – DNA Example: test for Huntington’s disease + Regents Biology
Uses: Forensics § Comparing DNA sample from crime scene with suspects & victim suspects S 1 S 2 S 3 crime scene V sample – DNA Regents Biology +
Electrophoresis use in forensics § Evidence from murder trial u Do you think suspect is guilty? blood sample 1 from crime scene blood sample 2 from crime scene blood sample 3 from crime scene “standard” blood sample from suspect OJ Simpson blood sample from victim 1 N Brown blood sample from victim 2 R Goldman Regents Biology “standard”
Uses: Paternity § Who’s the father? Mom F 1 – DNA Regents Biology + F 2 child
I’m a-glow! Got any Questions? Regents Biology 2006 -2007
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