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Genetic Engineering Biotechnology. We have been manipulating DNA for generations!. Artificial breeding creating new breeds of animals & new crop plants to improve our food. Animal breeding. Breeding food plants. “Descendants” of the wild mustard the “Cabbage family”. Breeding food plants.
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We have been manipulating DNA for generations! • Artificial breeding • creating new breeds of animals & new crop plants to improve our food
Breeding food plants • “Descendants” of the wild mustard • the “Cabbage family”
Breeding food plants Evolution of modern corn (right) from ancestral teosinte (left).
The code is universal • Since all living organisms… • use the same DNA • use the same code book • read their genes the same way
TACGCACATTTACGTACGCGGATGCCGCGACTATGATCACATAGACATGCTGTCAGCTCTAGTAGACTAGCTGACTCGACTAGCATGATCGATCAGCTACATGCTAGCACACYCGTACATCGATCCTGACATCGACCTGCTCGTACATGCTACTAGCTACTGACTCATGATCCAGATCACTGAAACCCTAGATCGGGTACCTATTACAGTACGATCATCCGATCAGATCATGCTAGTACATCGATCGATACTGCTACTGATCTAGCTCAATCAAACTCTTTTTGCATCATGATACTAGACTAGCTGACTGATCATGACTCTGATCCCGTAGATCGGGTACCTATTACAGTACGATCATCCGATCAGATCATGCTAGTACATCGATCGATACTGCTACTGATCTAGCTCAATCAAACTCTTTTTGCATCATGATACTAGACTAGCTGACTGATCATGACTCTGATCCCGTAGATCGGGTACCTATTACAGTACGATCATCCGATCAGATCATGCTAGTACATCGATCGATACTTACGCACATTTACGTACGCGGATGCCGCGACTATGATCACATAGACATGCTGTCAGCTCTAGTAGACTAGCTGACTCGACTAGCATGATCGATCAGCTACATGCTAGCACACYCGTACATCGATCCTGACATCGACCTGCTCGTACATGCTACTAGCTACTGACTCATGATCCAGATCACTGAAACCCTAGATCGGGTACCTATTACAGTACGATCATCCGATCAGATCATGCTAGTACATCGATCGATACTGCTACTGATCTAGCTCAATCAAACTCTTTTTGCATCATGATACTAGACTAGCTGACTGATCATGACTCTGATCCCGTAGATCGGGTACCTATTACAGTACGATCATCCGATCAGATCATGCTAGTACATCGATCGATACTGCTACTGATCTAGCTCAATCAAACTCTTTTTGCATCATGATACTAGACTAGCTGACTGATCATGACTCTGATCCCGTAGATCGGGTACCTATTACAGTACGATCATCCGATCAGATCATGCTAGTACATCGATCGATACT human genome3.2 billion bases
Mixing genes for medicine… • Allowing organisms to produce new proteins • bacteria producing human insulin • bacteria producing human growth hormone
How do we do mix genes? • Genetic engineering • find gene • cut DNA in both organisms • paste gene from one creature into other creature’s DNA • insert new chromosome into organism • organism copies new gene as if it were its own • organism reads gene as if it were its own • organism produces NEW protein: Remember: we all use the same genetic code!
Cutting DNA • DNA “scissors” • enzymes that cut DNA • restriction enzymes • used by bacteria to cut up DNA of attacking viruses • EcoRI, HindIII, BamHI • cut DNA at specific sites • enzymes look for specific base sequences GTAACG|AATTCACGCTT CATTGCTTAA|GTGCGAA GTAACGAATTCACGCTT CATTGCTTAAGTGCGAA
GTAACGAATTCACGCTT CATTGCTTAAGTGCGAA GTAACG AATTCACGCTT CATTGCTTAA GTGCGAA Restriction enzymes • Cut DNA at specific sites • leave “sticky ends” restriction enzyme cut site restriction enzyme cut site
gene you want chromosome want to add gene to GGACCTG AATTCCGGATA CCTGGACTTAA GGCCTAT GTAACG AATTCACGCTT CATTGCTTAA GTGCGAA GGACCTG AATTCACGCTT CCTGGACTTAA GTGCGAA combinedDNA Sticky ends • Cut other DNA with same enzymes • leave “sticky ends” on both • can glue DNA together at “sticky ends”
TTGTAACGAATTCTACGAATGGTTACATCGCCGAATTCACGCTT AACATTGCTTAAGATGCTTACCAATGTAGCGGCTTAAGTGCGAA AATTCTACGAATGGTTACATCGCCG GATGCTTACCAATGTAGCGGCTTAA isolated gene sticky ends cut sites chromosome want to add gene to AATGGTTACTTGTAACG AATTCTACGATCGCCGATTCAACGCTT TTACCAATGAACATTGCTTAA GATGCTAGCGGCTAAGTTGCGAA sticky ends stick together chromosome with new gene added TAACGAATTCTACGAATGGTTACATCGCCGAATTCTACGATCCATTGCTTAAGATGCTTACCAATGTAGCGGCTTAAGATGCTAGC Sticky ends help glue genes together cut sites gene you want cut sites Recombinant DNA molecule DNA ligase joins the strands
TAACGAATTCTACGAATGGTTACATCGCCGAATTCTACGATCCATTGCTTAAGATGCTTACCAATGTAGCGGCTTAAGATGCTAGCTAACGAATTCTACGAATGGTTACATCGCCGAATTCTACGATCCATTGCTTAAGATGCTTACCAATGTAGCGGCTTAAGATGCTAGC “new” protein from organism ex: human insulin from bacteria aa aa aa aa aa aa aa aa aa aa How can bacteria read human DNA? Why mix genes together? • Gene produces protein in different organism or different individual human insulin gene in bacteria bacteria human insulin
Uses of genetic engineering • Genetically modified organisms (GMO) • enabling plants to produce new proteins • Protect crops from insects: BT corn • corn produces a bacterial toxin that kills corn borer (caterpillar pest of corn) • Extend growing season: fishberries • strawberries with an anti-freezing gene from flounder • Improve quality of food: golden rice • rice producing vitamin A improves nutritional value
Bacteria • Bacteria are great! • one-celled organisms • reproduce by mitosis • easy to grow, fast to grow • generation every ~20 minutes
Bacterial DNA • Single circular chromosome • only one copy = haploid • no nucleus • Other DNA = plasmids! bacteriachromosome plasmids
There’s more… • Plasmids • small extra circles of DNA • carry extra genes that bacteria can use • can be swapped between bacteria • bacterial sex!! • rapid evolution = antibiotic resistance • can be picked up from environment
transformedbacteria gene fromother organism recombinantplasmid cut DNA vector plasmid How can plasmids help us? • A way to get genes into bacteria easily • insert new gene into plasmid • insert plasmid into bacteria = vector • bacteria now expresses new gene • bacteria make new protein + glue DNA
transformedbacteria gene fromother organism recombinantplasmid + vector plasmid growbacteria harvest (purify)protein Grow bacteria…make more
I’m a very special pig! Got any Questions?
Biotechnology Gel Electrophoresis
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 • gel electrophoresis • How does a gel work?
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”
Gel electrophoresis • 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 DNA – + “swimming through Jello”
Gel Electrophoresis DNA &restriction enzyme - longer fragments wells power source gel shorter fragments completed gel +
fragments of DNAseparate out based on size Running a gel Stain DNA • ethidium bromide binds to DNA • fluoresces under UV light cut DNA with restriction enzymes 1 2 3
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 GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTT CGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGAA GCTTGTAACGGCATCATCATCATCATCATCCGGCCTACGCTT CGAACATTGCCGTAGTAGTAGTAGTAGTAGGCCGGATGCGAA
Allele 1 cut sites repeats cut sites GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTT CGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGAA GCTTGTAACG GCCTCATCATCATCGCCG GCCTACGCTT CGAACATTGCCG GAGTAGTAGTAGCGGCCG GATGCGAA DNA patterns for DNA fingerprints Cut the DNA 1 2 3 – + DNA allele 1
Differences between people Person 1 cut sites cut sites GCTTGTAACGGCCTCATCATCATTCGCCGGCCTACGCTT CGAACATTGCCGGAGTAGTAGTAAGCGGCCGGATGCGAA Person 2: more repeats GCTTGTAACGGCCTCATCATCATCATCATCATCCGGCCTACGCTT CGAACATTGCCGGAGTAGTAGTAGTAGTAGTAGGCCGGATGCGAA 1 2 3 DNA fingerprint – + DNA person 1 person 2
1 2 3 4 5 1 2 3 4 5 Uses: Evolutionary relationships • Comparing DNA samples from different organisms to measure evolutionary relationships turtle snake rat squirrel fruitfly – DNA +
Uses: Medical diagnostic • Comparing normal allele to disease allele chromosomewith normal allele 1 chromosome with disease-causing allele 2 allele 2 allele 1 – DNA Example: test for Huntington’s disease +
Uses: Forensics • Comparing DNA sample from crime scene with suspects & victim suspects crime scene sample S1 S2 S3 V – DNA +
DNA fingerprints • Comparing blood samples on defendant’s clothing to determine if it belongs to victim • DNA fingerprinting
RFLP / electrophoresis use in forensics • 1st case successfully using DNA evidence • 1987 rape case convicting Tommie Lee Andrews “standard” semen sample from rapist blood sample from suspect “standard” How can you compare DNA fromblood & from semen?RBC? “standard” semen sample from rapist blood sample from suspect “standard”
Electrophoresis use in forensics • Evidence from murder trial • 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 “standard”
Mom F1 F2 child Uses: Paternity • Who’s the father? – DNA +
I’m a-glow! Got any Questions?
Using Stem Cells • A stem cellis a cell that can continuously divide and differentiate into various tissues. • Some stem cells have more potential to differentiate than others. • Adults’ bodies have some multipotent cells that can be removed, frozen or cultured, and used for medical treatments. • The cells of new embryos have more potential uses. • The use of embryos for stem cell research poses ethical problems. • An alternative source of embryonic stem cells is through SCNT (somatic cell nuclear transplant).
What are Stem Cells? Stem Cells are extraordinary because: They can divide and make identical copies of themselves over and over again (Self-Renewal) Remain Unspecialized with no ‘specific’ function or become . . . . Specialized (Differentiated) w/ the potential to produce over200different types of cells in the body.
The Major Types of Stem Cells • Embryonic Stem Cells • From blastocysts left over from In-Vitro Fertilization in the laboratory • From abortedfetuses • B. Adult Stem Cells • Stem cells have been found in the blood, bone marrow, liver, kidney, cornea, dental pulp, umbilicalcord, brain, skin, muscle, salivary gland . . . .
http://commons.wikimedia.org/wiki/Image:Stem_cells_diagram.pnghttp://commons.wikimedia.org/wiki/Image:Stem_cells_diagram.png
Advantages and Disadvantages to Embryonic and Adult Stem Cells.
http://www.pbs.org/newshour/bb/science/jan-june14/stemcells_01-29.htmlhttp://www.pbs.org/newshour/bb/science/jan-june14/stemcells_01-29.html Reprinted with permission of Do No Harm. Click on image for link to website.
Why is Stem Cell Research So Important to All of Us? • Stem cells allow us to study how organisms grow and develop over time. • Stem cells can replace diseased or damaged cells that can not heal or renew themselves. • We can test different substances (drugs and chemicals) on stem cells. • We can get a better understanding of our “genetic machinery.”