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

Glowing Animals

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

DNA Manipulation

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

Gene Therapy

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

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

DNA Vaccine

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?