Copyright 2003 Pearson Education Inc publishing as Benjamin
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• “Golden rice” has been genetically modified to contain beta-carotene – prevent vitamin A deficiency Figure 12. 18 B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Biotechnology - use of living organisms to create products or help processes Ex. HGH, insulin Recombinant DNA - segment of DNA containing sequences from different organisms How is DNA manipulated?
Restriction enzymes cut DNA at specific sites and create sticky ends G T G G T T A A C C A A T T A C C T C C A G G T C T G A T C G C T G T T C A G A A A C T G G C A A A G G T C T T A T GA GA T TC C C G G G T T C T T T C G A T C C A G AA C G G A A A T TC T C C TAG AG C A C G A C A A G C TA A G G T C T T G G C T T TA G Complementary ends will fuse to produce a long strand of DNA
• The transferred DNA is then integrated into the recipient cell’s chromosome Donated DNA Degraded DNA Crossovers Recipient cell’s chromosome Figure 12. 1 D Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Recombinant chromosome
Plasmids are extra rings of DNA that replicate in bacteria. DNA can be inserted into plasmids. bacterium bacterial chromosome plasmid
Bacterium Human cell Plasmid DNA Human protein Bacterial chromosome 1. Use restriction enzymes. 2. Insert gene into plasmid. recombinant DNA transformation 3. Transfer the plasmid back into bacterial cell. replication 4. Let bacterial cells replicate. bacterial clones
Recombinant DNA products • “seed” protein for artificial snow • Insulin for diabetes treatment • Enzymes that clean up toxic waste spills • Growth Hormones (Human, Bovine) • TPA: Tissue Plasminogen Activator for treatment of heart attacks Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• The polymerase chain reaction (PCR) can quickly clone a small sample of DNA in a test tube Initial DNA segment 1 2 4 Number of DNA molecules Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 8 Figure 12. 12
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Gel electrophoresis sorts DNA molecules by size • Restriction fragments of DNA are compared by size Mixture of DNA molecules of different sizes Longer molecules Power source Gel Shorter molecules Glass plates Completed gel Figure 12. 10 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
DNA forensics
• Uses of transformed animals: • Produce medicines more easily Ex. sheep and gene to treat cystic fibrosis Goats and AT 3 gene to prevent blood clots Figure 12. 16 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Grow bigger fish faster. Salmon with gene from another fish species
Art form?
Genetically modified crops • Golden rice with Vitamin A • Cotton resistant to boll weevil • Soybeans resistant to herbicide (Roundup) • Corn resistant to European corn borer • Rapeseed with healthier vegetable oil Benefits and risks Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
How Dolly was cloned DNA udder cells white sheep embryo surrogate mother egg cell black sheep Dolly
Cloning of human cells • Regenerative medicine – Bone, pancreas cells, skin Stem cells - the $6 billion promise?
Gene therapy may someday help treat a variety of diseases • treat disease by altering an afflicted individual’s genes Cloned gene (normal allele) 1 Insert normal gene into virus Viral nucleic acid – Ex vivo Retrovirus – In vivo 2 Infect bone marrow cell with virus – Stem cells 3 Viral DNA inserts into chromosome Bone marrow cell from patient Bone marrow Figure 12. 19 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 4 Inject cells into patient
Human Genome Project • 3. 2 billion bases in 22 autosomes + X, Y • Draft sequence completed in 2003 • Available at www. ornl. gov/sci/techresources/Human_Genome/ home. shtml • www. ucsc. genome. edu
What does the human genome sequence tell us? • 20 K to 25 K genes • 99. 9% alike, across all races • 98. 5% of DNA is not transcribed - Spacers between genes - Structural (centromeres, telomeres) - Regulatory (enhancers, promoters) - Leftovers of evolution? - STR short tandem repeats - Alu (280 bp repeated 1 million times)
What’s next? • • Gene therapy Personalized medical treatments Genetic discrimination Designer children
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