Genetic Engineering: How and why scientists manipulate DNA in living cells http://farm3.static.flickr.com

Karyotype chart of chromosome pairs used to identify unusual #s of chromosomes **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) FYI Karyotype is obtained by 1) getting a sample of cells from a fetus 2) metaphase chromosomes are photographed 3) chrom. pictures are enlarged and arranged in pairs based on length and centromere location

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

http://www.biologyreference.com/images/biol_04_img0412.jpg

Nondisjunction – causes these unusual #s of chromosomes; chromosomes fail to separate during meiosis http://www.medgen.ubc.ca/wrobinson/backup/mosaic/images/nondis_m2.gif

http://www. ratsteachgenetics. com/Genetics_quizzes/Lecture%207/7q1 http://www.ratsteachgenetics.com/Genetics_quizzes/Lecture%207/7q1.jpg

Selective breeding We choose desired traits & breed plants and animals to have these traits *Takes decades Examples: popcorn, dog breeds, cows produce 3x more milk than 50 years ago, bigger peaches, apple varieties http://img.dailymail.co.uk/i/pix/2008/02_02/CaulliDM_468x518.jpg

Selective breeding – 2 methods 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 http://www.biologyreference.com/images/biol_02_img0235.jpg

2. Inbreeding – done to maintain traits *because genetics are so close, often allows expression of recessive allele Study revealed that 20,000 boxers genetically look like 70 -deaf dalmations & white boxers, heart disease, hip dysplasia http://www.boxerbuddies.org/Boxer%20Info/oscar10.jpg

Test cross A way of determining genotype 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 http://farm3.static.flickr.com/2023/2503367977_4a5dc2345a.jpg?v=0

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

1. Cut DNA: Restriction enzymes DNA is too large to be analyzed Highly specific restriction enzymes from bacteria cut DNA into precise pieces between certain base pairs Ex. EcoRI 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 What do you remember about enzymes …they are substrate specific. Restriction enzymes are specific and only cut DNA at certain locations.

Restriction enzymes http://www.mhhe.com/biosci/esp/2001_gbio/folder_structure/ge/m6/s1/assets/images/gem6s1_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/c7.20.8.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/dnabasics2.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/t235/T235690A.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 http://www.mhhe.com/biosci/genbio/maderbiology7/graphics/mader07b/online_vrl/images/0287l.jpg

Genetic engineering: faster than selective breeding. Cut DNA from one organism, insert into another. Recombinant DNA: combining DNA from different sources http://campus.queens.edu/faculty/jannr/Genetics/images/dnatech/bx15_01.jpg

Transgenic organisms 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/c7.20.4.insulin.jpg

http://www.e-ishraq.com/v4/images/6_3.gif

Cloning 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 30% of US milk produced by genetically modified (GM) cows Pigs GM to produce high levels of lean meat 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/GoldenRice-WhiteRice.jpg/800px-GoldenRice-WhiteRice.jpg http://www.bio.davidson.edu/courses/GENOMICS/2008/Waters/TIME.jpg

Gene therapy 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

http://library. thinkquest. org/28000/media/genetherapy/l_gene http://library.thinkquest.org/28000/media/genetherapy/l_gene.therapy-ms.gif

Future possibilities? http://ec1.images-amazon.com/images/I/51EbEYn8hAL.jpg

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

http://media-2. web. britannica. com/eb-media/64/47664-004-7088EE3D http://media-2.web.britannica.com/eb-media/64/47664-004-7088EE3D.jpg