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Chapter 13. Gene Technology. DNA Technology. DNA: Can be used as evidence in a criminal case Improve food crops Determine if a person is carrying a genetic disease To do research to treat and cure genetic diseases. DNA Identification.
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Chapter 13 Gene Technology
DNA Technology • DNA: • Can be used as evidence in a criminal case • Improve food crops • Determine if a person is carrying a genetic disease • To do research to treat and cure genetic diseases
DNA Identification • Human genome: the complete genetic material in an individual • There is only a 0.1 % variation from person to person • About 98% of our genetic makeup does not code for any protein, these regions of DNA are called noncoding DNA • Noncoding DNA comes in different lengths called length polymorphisms • Differences in lengths of noncoding DNA and other variations account for many of the differences in DNA among individuals
Steps in DNA Identification • Copying DNA • Polymerase Chain Reactions (PCR) quickly produces many copies of DNA
Steps in DNA Identification 2. Cutting DNA • Restriction Enzymes: bacteria proteins that recognize specific DNA sequences and cut the DNA at the sequence
Steps in DNA Identification 3. Sorting DNA by size • Gel Electrophoresis: separates DNA fragments according to their size and charge (+ or -) • DNA Fingerprint: resulting pattern of DNA fragments
Steps in DNA Identification • Shorter fragments move fasters and farther than longer fragments • Negatively charged DNA moves towards the positive side of the gel electrophoresis tray • Gel is stained and can be transferred to a film or paper for analysis
Gel Electrophoresis • http://learn.genetics.utah.edu/units/biotech/gel/ • http://www.pbs.org/wgbh/nova/education/body/create-dna-fingerprint.html • http://www.youtube.com/v/PSwlCk_Z02c&feature=related
Bioethics Warm-Up Would you want to know if you were genetically predisposed to a certain disorder (like heart disease or diabetes)? What if it was for a disorder that has no known treatment?
Checking for Understanding • How are DNA fingerprints similar to real fingerprints? • How are they different?
Steps in DNA Identification • 4. Accuracy of DNA fingerprints • DNA Fingerprint: resulting pattern of DNA fragments • The odds that two people will share an identical DNA profile are approximately 1 in 100 billion • The odds of being attacked by a shark in the United States are roughly 1 in 8 million
Recombinant DNA • Genetic engineering: Process of altering the genetic material of cells or organisms to allow them to make new substances • Recombinant DNA: DNA from two different organisms are joined • Ex: inserting a jellyfish gene that codes for green fluorescent protein into other species
Ex: Golden Rice Created to provide people with Vitamin A Developed to help the very poor
Ex: Flavr Savr Tomato Created to prevent the softening of the tomato Made more resistant to rotting Could be “vine-ripened”
Ex: Glofish Inserted fluorescent gene from a jellyfish into zebrafish Sold as a pet
Ex: Roundup Ready Soybeans Soybeans that are resistant to Roundup herbicide Created to reduce the application of harmful herbicides
DNA DNA is universal – the genetic information from one species will work in another species “DNA is DNA”
DNA 101 – Quick Refresher • DNA formed from units called nucleotides • Each nucleotide is made of: • 5 carbon sugar (deoxyribose) • Phosphate group • Nitrogenous base • Adenine • Guanine • Cytosine • Thymine
DNA 101 – Quick Refresher • In all DNA: • A pairs with T • C pairs with G • Weak hydrogen bonds form between complimentary base pairs
Useful Properties of DNA Restriction enzymes: enzymes used to cut apart DNA strands
Recombinant DNA • Gene of interest: a segment of one species’ DNA that scientists wish to insert into another species’ DNA • Plasmid: small rings of DNA found naturally in bacteria cells
Recombinant DNA • http://www.youtube.com/watch?v=x2jUMG2E-ic
Bioethical Question • Should a company be allowed to patent (and own the exclusive rights of) a genetically modified organism?
Genetic Engineering • Medical applications: • Allows biologists to study how genes function
Gene Therapy • Treats genetic disorders by introducing a gene into a patient’s cells • Works best for disorders that result from the loss of a single protein • Ex: cystic fibrosis is currently being worked on
Cloning • Cloning by nuclear transfer – introducing a nucleus of a body cell into an egg cell to generate an organism identical to the nucleus donor • First cloned mammal was Dolly the sheep
Cloning • Goal of most animal cloning is to alter the genome in a useful way • Ex: Cloning of goats so they secrete human blood clotting factors into milk • Ex: Cloning of pigs for organ transplants in humans
Vaccines • DNA vaccines are made from the DNA of the pathogen, but does not have disease-causing capability • Ex: AIDS, malaria, certain cancers
Agricultural Applications • Making crops: • More tolerant to environment conditions • Resistant to herbicides • To increase food yields • Resistant to disease • Nutritional value greater
Ex: Golden Rice Created to provide people with Vitamin A Developed to help the very poor
Ex: Flavr Savr Tomato Created to prevent the softening of the tomato Made more resistant to rotting Could be “vine-ripened”
Ex: Glofish Inserted fluorescent gene from a jellyfish into zebrafish Sold as a pet
Ex: Roundup Ready Soybeans Soybeans that are resistant to Roundup herbicide Created to reduce the application of harmful herbicides
Ethical Issues • Bioethics – study of ethical issues related to DNA technology • Most scientists feel rigorous testing and safeguards should be in place for crop alteration
Ethical Issues • Most scientists consider gene therapy unethical if it involves reproductive cells that would affect future generations • Decisions about ethical issues are made by the involvement of the scientists and informed public
Bioethical Question • Should we be able to insert non-human DNA into human DNA? • Would this change what it means to be “human”? • Should humans be able to alter our intelligence via genetic engineering?
Bioethical Question • If there aren’t any risks associated with GM foods, should companies be required to label foods made with GMOs?