Genetic Engineering: How and why scientists manipulate DNA in living cells

Genetic Engineering:How and why scientists manipulate DNA in living cells

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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)

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.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 that20,000 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 heterozygousIf unknown is homozygous dominant, all offspring will

show dominant traitIf unknown is heterozygous, some will show dominant

trait, some show recessive traitComplete Problem Solving Lab 13.1 p.339

http://farm3.static.flickr.com/2023/2503367977_4a5dc2345a.jpg?v=0

Manipulating DNA

Process How

Cut DNARestriction 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

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

http://www.bio.miami.edu/~cmallery/150/gene/c7.20.8.electrophoresis.jpg

p. 346

1.Insert restriction-enzyme-cutDNA into gel 2. Add electricity.

Shorter fragments move farther

3. Result: DNA fingerprint

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?

http://images.encarta.msn.com/xrefmedia/sharemed/targets/images/pho/t235/T235690A.jpg

PS lab 13.3 p.353

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)

http://www.bio.miami.edu/~cmallery/150/gene/c7.20.4.insulin.jpg

Recombinant bacteria manufacture insulin

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 producehigh levels of lean meat

http://www.scienceprogress.org/wp-content/uploads/2009/01/goat_591.jpg

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

Transgenic plants: Golden Rice – GM to have high levels of beta-carotene – essential for health, eye sight

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.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.jpg