Genetic Engineering How and why scientists manipulate DNA

Genetic Engineering: How and why scientists manipulate DNA in living cells http: //farm 3. static. flickr. com

Karyotype chart of chromosome pairs used to identify unusual #s of chromosomes o n n n **Down syndrome (Trisomy 21) – 3 chrom. at pair 21 Turner’s syndrome – only one X – sterile female XO Klinefelter’s syndrome – extra X (male: XXY-sterile)

Karyotype http: //users. rcn. com/jkimball. ma. ultranet/Biology. Pages/D/Down. gif

http: //www. biologyreference. com/images/biol_04_img 0412. jpg

o Nondisjunction – causes these unusual #s of chromosomes; chromosomes fail to separate during meiosis http: //www. medgen. ubc. ca/wrobinson/backup/mosaic/images/nondis_m 2. gif

http: //www. ratsteachgenetics. com/Genetics_quizzes/Lecture%207/7 q 1. jpg

Selective breeding We choose desired traits & breed plants and animals to have these traits *Takes decades o Examples: popcorn, dog breeds, cows produce 3 x more milk than 50 years ago, bigger peaches, apple varieties o http: //img. dailymail. co. uk/i/pix/2008/02_02/Caulli. DM_468 x 518. jpg

Selective breeding – 2 methods o 1. Hybridization – cross dissimilar individuals to bring together best traits Ex. Crossing disease-resistant apple with high yield apple = apple tree that produces a lot and requires less pesticides n http: //www. biologyreference. com/images/biol_02_img 0235. jpg

o 2. Inbreeding – done to maintain traits *because genetics are so close, often allows expression of recessive allele n Study revealed that 20, 000 boxers genetically look like 70 -deaf dalmations & white boxers, heart disease, hip dysplasia n http: //www. boxerbuddies. org/Boxer%20 Info/oscar 10. jpg

Test cross A way of determining genotype o Cross a known individual (homozygous recessive) with an unknown – homozygous dominant or heterozygous If unknown is homozygous dominant, all offspring will show dominant trait If unknown is heterozygous, some will show dominant trait, some show recessive trait Complete Problem Solving Lab 13. 1 p. 339 o http: //farm 3. static. flickr. com/2023/2503367977_4 a 5 dc 2345 a. jpg? v=0

Manipulating DNA Process How Cut DNA Restriction Enzymes (like scissors) Sort DNA Gel Electrophoresis Analyze DNA fingerprint

1. Cut DNA: Restriction enzymes o o DNA is too large to be analyzed Highly specific restriction enzymes from bacteria cut DNA into precise pieces between certain base pairs n o o Ex. Eco. RI can only recognize GAATTC – it cuts between the G and A Leaves “sticky ends” – single-stranded overhangs used to bond “stick” to another DNA stand cut with the same restriction enzyme Practice p. 343

Restriction enzymes http: //www. mhhe. com/biosci/esp/2001_gbio/folder_structure/ge/m 6/s 1/assets/images/gem 6 s 1_1. jpg

2. Sort DNA: Gel Electrophoresis 3. Result: DNA fingerprint 1. Insert restriction-enzyme-cut DNA into gel 2. Add electricity. Shorter fragments move farther p. 346 http: //www. bio. miami. edu/~cmallery/150/gene/c 7. 20. 8. electrophoresis. jpg

3. Analyze DNA: DNA fingerprinting *Sample from blood, hair, skin, semen *Use PCR (polymerase chain reaction) to make more http: //dnamazing. com/wp-content/uploads/2007/08/dnabasics 2. JPG

Can you match the evidence with the suspect? PS lab 13. 3 p. 353 http: //images. encarta. msn. com/xrefmedia/sharemed/targets/images/pho/t 235/T 235690 A. jpg

Human Genome Project (1990 -2003) *Sequenced all 3 billion base pairs of human DNA and identified all human genes. *Used to determine carriers for diseases & develop gene therapy http: //www. sanger. ac. uk/Info/Press/gfx/030414_hgp_300. jpg

Product of Human Genome: chromosome maps o http: //www. mhhe. com/biosci/genbio/maderbiology 7/graphics/mader 07 b/online_vrl/images/0287 l. jpg

Genetic engineering: faster than selective breeding. Cut DNA from one organism, insert into another. o Recombinant DNA: combining DNA from different sources o http: //campus. queens. edu/faculty/jannr/Genetics/images/dnatech/bx 15_01. jpg

Transgenic organisms o o o Contain genes from other species Insert recombinant DNA into a new host Use plasmid – circle of DNA in bacteria Insert recombinant DNA into plasmid, reinsert plasmid into bacteria- bacteria clones DNA as it divides (mitosis); get lots of copies of DNA Used to produce insulin to treat diabetes, human growth hormone, blood-clotting factors for hemophiliacs, potentially even cancer-fighting molecules (interleukin-2 and interferon)

Recombinant bacteria manufacture insulin http: //www. bio. miami. edu/~cmallery/150/gene/c 7. 20. 4. insulin. jpg

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Cloning o Uses a single somatic cell from an adult organism to grow an entirely new genetically identical organism http: //static. howstuffworks. com/gif/cloning-sheep. gif

Uses of transgenic animals Insert spider genes into cells of lactating goats – manufacture silk along with milk = light, tough, flexible material military uniforms, medical sutures o 30% of US milk produced by genetically modified (GM) cows o Pigs GM to produce high levels of lean meat o http: //www. scienceprogress. org/wp-content/uploads/2009/01/goat_591. jpg

Transgenic plants: Golden Rice – GM to have high levels of beta-carotene – essential for health, eye sight http: //upload. wikimedia. org/wikipedia/en/thumb/8/88/Golden. Rice-White. Rice. jpg/800 px-Golden. Rice-White. Rice. jpg http: //www. bio. davidson. edu/courses/GENOMICS/2008/Waters/TIME. jpg

Gene therapy o o o Absent or faulty genes replaced by normal working genes – allows body to make proteins or enzymes needed, eliminating disorder Used to treat SCID (severe combined immunodeficiency syndrome) Trials for sickle-cell, cystic fibrosis, and hemophilia treatments are going on now

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Future possibilities? http: //ec 1. images-amazon. com/images/I/51 Eb. EYn 8 h. AL. jpg

Implications? Ethical issues? o o o Patenting life Genetic ownership GINA (Genetic Information Nondiscrimination Act) passed in 2008 n Protects Americans against discrimination from employers or insurance companies based on genetic information

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