Chapter 20: Biotechnology

Essential Knowledge u 3.a.1 – DNA, and in some cases RNA, is the primary source of heritable information (20.1 & 20.2)

Focus of Chapter u An introduction to the methods and developments in: u Recombinant DNA u Genetic Engineering u Biotechnology

Recombinant DNA u DNA in which genes from different sources are linked u Ex: the “green” mice

Genetic Engineering u The direct manipulation of genes for practical purposes u Ex: Using E. coli to produce human insulin

Biotechnology u The use of living organisms or their components to perform practical tasks u Ex: the use of bacteria to digest oil spills

Plasmids u Small circular piece of DNA u Carry many important traits u Used extensively in biotechnology and recombinant DNA u Serve as a “vehicle” for transporting genes

Steps for Plasmid Use 1. Get the DNA for the trait 2. Insert DNA into the plasmid 3. Bacterial transformation 4. Identification of the new trait *Fig 20.4, page 399

Restrictive Enzymes u Cut DNA at specific nucleotide sequences called “restriction sites” u Used to "cut and splice" DNA u Obtained from bacteria u Ex. EcoRI and Hind III

Insertion u Placing foreign DNA into a plasmid u Open plasmid with enzymes to create “sticky ends” u Splice the new DNA and plasmid together.

Transformation u Placing the plasmid into a bacterial cell

Methods u Temperature shock & salt treatment u Electric current u Injection

Identification u Screening the altered cells for the desired gene u Ex: Antibiotic sensitivity or the expression of a “new” trait (color, glowing etc.)

Example Applications 1. Insulin 2. Human Growth Hormone 3. Other Proteins

DNA Sources 1. Organism - use a section of their chromosome 2. cDNA - created copy of DNA (to avoid introns)

Organism DNA u Isolated by restrictive enzyme cuts u Separation by gel electrophoresis u Pieces stored in a genomic library

cDNA u CDNA u Complementary DNA u Artificial gene with no introns u Made from the mRNA for that specific protein using Reverse Transcriptase

DNA Sequencing: Sanger Method u Uses dideoxynucleotides u Build new DNA from single strand DNA u Used to separate out nucleotides

PCR Method u Polymerase Chain Reaction u Used to make many copies of a small segment of DNA u Quicker than Sanger method

RFLP Method u Restriction Fragment Length Polymorphism u Used for detecting minor differences in DNA u Uses: u DNA fingerprinting (crimes) u Pedigree studies (DNA markers)

Southern Blotting method u Developed by EM Southern in 1975 u Used to compare fragments from different genomes u Looks like a photograph u More permanent results

DNA Technology: Applications 1. Basic Research 2. Medical 3. Forensics 4. Agricultural

Basic Research 1. DNA and protein studies 2. Evolution 3. Gene structure and control mechanisms

Human Genome Project (HGP) u 15 year project which started in 1990 u Project was basically completed in February 2000

HGP Goals 1. Linkage mapping of the human genome. 2. Physical mapping of the human genome. 3. Human genome sequence. 4. Genomes of other species.

Medical Uses 1. Diagnosis of Diseases 2. Gene Therapy 3. Vaccines 4. Pharmaceutical Products

Forensic Uses u DNA fingerprints for crime solving u DNA identification records

Agricultural Uses 1. Animals u Increased milk production u Increased feed utilization u Increased meat production

Injecting DNA into egg

PharmAnimals

Agricultural Uses 2. Plants u Herbicide resistance u Retard spoilage of fruits u Insect resistance u Nitrogen-Fixation ability

Future Of DNA Technology u Cloning of higher animals u Growth of replacement tissues and organs u Gene therapy to correct DNA defects u?u?

Gene Therapy

Summary u Recognize some of the basic strategies and methods of gene manipulation and analysis. u Identify representative examples of the applications of DNA technology. u Be prepared to discuss the implications of genetically modified organisms (GMO’s) on science, technology and society.