CHAPTER 12 DNA Technology Figures 12 1 12 4 PowerPoint Lecture Slides for Essential Biology Second Edition Essential Biology with Physiology Neil Campbell Jane Reece and Eric Simon Presentation prepared by Chris C Romero Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings The DNA of two people of the same sex is 99 9 identical Animals plants and even bacteria can be genetically modified to produce human proteins Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings The first use of DNA fingerprinting in a murder case proved one man innocent and another guilty Genetically modified strains account for half of the U S corn crop Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings 1 BIOLOGY AND SOCIETY HUNTING FOR GENES DNA technology is a set of methods for studying and manipulating genetic material These techniques have brought about many remarkable scientific advances Genetically modified food DNA fingerprinting The Human Genome Project Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings The goal of the Human Genome Project is to determine the nucleotide sequence of all DNA in the human genome Hundreds of diseaseassociated genes have already been identified Example Parkinson disease Figure 12 1 Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings RECOMBINANT DNA TECHNOLOGY Recombinant DNA technology is a set of techniques for combining genes from different sources into a single DNA molecule An organism that carries recombinant DNA is called a genetically modified GM organism Recombinant DNA technology is applied in the field of biotechnology Biotechnology uses various organisms to perform practical tasks Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings 2 Cell containing gene of interest Host cell 1 DNA Recombinant DNA host DNA plus gene of interest 2 Gene of interest Cell multiplies and produces protein 3 Genes may be inserted into another organism Protein may be harvested OR Gene for pest resistance inserted into plants Protein dissolves blood clots in heart attack therapy Figure 12 2 Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings From Humulin to Genetically Modified Foods By transferring the gene for a desired protein product into a bacterium proteins can be produced in large quantities Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings Making Humulin In 1982 the world s first genetically engineered pharmaceutical product was produced Humulin human insulin was produced by genetically modified bacteria Figure 12 3 Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings 3 Prior to the development of Humulin diabetes was treated using insulin from cows and pigs These types of insulin can cause adverse reactions in recipients Humulin was the first recombinant DNA drug approved by the FDA Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings DNA technology is also helping medical researchers develop vaccines A vaccine is a harmless variant or derivative of a pathogen Vaccines are used to prevent infectious diseases Figure 12 4 Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings Genetically Modified GM Foods Today DNA technology is quickly replacing traditional plant breeding programs In 2002 roughly half of the American crops of soybeans and corn were genetically modified in some way Figure 12 5a Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings 4 Corn has been genetically modified to resist insect infestation This corn has been damaged by the European corn borer Figure 12 5b Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings Golden rice has been genetically modified to contain beta carotene Our bodies use betacarotene to make vitamin A Figure 12 6 Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings Farm Animals and Pharm Animals While transgenic plants are used today as commercial products transgenic whole animals are currently only in the testing phase These transgenic sheep carry a gene for a human blood protein This protein may help in the treatment of cystic fibrosis Figure 12 7 Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings 5 While transgenic animals are currently used to produce potentially useful proteins none are yet found in our food supply It is possible that DNA technology will eventually replace traditional animal breeding Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings Recombinant DNA Techniques Bacteria are the workhorses of modern biotechnology To work with genes in the laboratory biologists often use bacterial plasmids Plasmids are small circular DNA molecules that are separate from the much larger bacterial chromosome Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings Plasmids Bacterial chromosome Remnant of bacterium Figure 12 8 Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings 6 Plasmids can easily incorporate foreign DNA Plasmids are readily taken up by bacterial cells Plasmids then act as vectors DNA carriers that move genes from one cell to another Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings Bacterial cell Recombinant DNA techniques can help biologists produce large quantities of a desired protein Plasmid Human cell 1 Isolate DNA from two sources DNA 2 Cut both DNAs Gene V Gene V Other genes DNA fragments 3 Mix the DNAs and join them together Recombinant DNA plasmids 4 Bacteria take up recombinant plasmids Recombinant bacteria 5 Clone the bacteria Bacterial clones 6 Find the clone with gene V 7 Grow bacteria and isolate protein V Protein V Figure 12 9 Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings A Closer Look Cutting and Pasting DNA with Restriction Enzymes Recombinant DNA is produced by combining two ingredients A bacterial plasmid The gene of interest To combine these ingredients a piece of DNA must be pasted into a plasmid Copyright 2004 Pearson Education Inc publishing as Benjamin Cummings 7 This pasting process can be accomplished using restriction enzymes These enzymes cut DNA at specific nucleotide sequences The places where DNA is cut are called restriction sites Many of these restriction sites leave staggered cuts that yield two double stranded DNA fragments with single stranded ends called sticky ends These are the key to joining DNA restriction fragments Copyright 2004 Pearson Education