Chapter 20:Chapter 20:BiotechnologyBiotechnology

Essential Knowledge

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

Focus of ChapterFocus of Chapter

An introduction to the methods and developments in: Recombinant DNA Genetic Engineering Biotechnology

Recombinant DNARecombinant DNA

DNA in which genes from different sources are linked

Ex: the “green” mice

Genetic EngineeringGenetic Engineering

The direct manipulation of genes for practical purposes

Ex: Using E. coli to produce human insulin

BiotechnologyBiotechnology

The use of living organisms or their components to perform practical tasks

Ex: the use of bacteria to digest oil spills

PlasmidsPlasmids

Small circular piece of DNA Carry many important traits Used extensively in

biotechnology and recombinant DNA

Serve as a “vehicle” for transporting genes

Steps for Plasmid UseSteps 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 EnzymesRestrictive Enzymes

Cut DNA at specific nucleotide sequences called “restriction sites”

Used to "cut and splice" DNA Obtained from bacteria Ex. EcoRI and Hind III

InsertionInsertion

Placing foreign DNA into a plasmid

Open plasmid with enzymes to create “sticky ends”

Splice the new DNA and plasmid together.

TransformationTransformation

Placing the plasmid into a bacterial cell

MethodsMethods

Temperature shock & salt treatment

Electric current Injection

IdentificationIdentification

Screening the altered cells for the desired gene

Ex: Antibiotic sensitivity or the expression of a “new” trait (color, glowing etc.)

Example ApplicationsExample Applications

1. Insulin

2. Human Growth Hormone

3. Other Proteins

DNA SourcesDNA Sources

1. Organism - use a section of their chromosome

2. cDNA - created copy of DNA (to avoid introns)

Organism DNAOrganism DNA

Isolated by restrictive enzyme cuts

Separation by gel electrophoresis

Pieces stored in a genomic library

cDNAcDNA

CComplementary DNADNA Artificial gene with no introns Made from the mRNA for that

specific protein using Reverse Transcriptase

DNA Sequencing: DNA Sequencing: Sanger MethodSanger Method

Uses dideoxynucleotides Build new DNA from single

strand DNA Used to separate out

nucleotides

PCR MethodPCR Method Polymerase Chain Reaction Used to make many copies of

a small segment of DNA Quicker than Sanger method

RFLP MethodRFLP Method Restriction Fragment Length

Polymorphism Used for detecting minor

differences in DNA Uses:Uses:

DNA fingerprinting (crimes) Pedigree studies (DNA markers)

Southern Blotting Southern Blotting methodmethod

Developed by EM Southern in 1975

Used to compare fragments from different genomes

Looks like a photograph More permanent results

DNA Technology: DNA Technology: ApplicationsApplications

1. Basic Research

2. Medical

3. Forensics

4. Agricultural

Basic ResearchBasic Research

1. DNA and protein studies

2. Evolution

3. Gene structure and control mechanisms

Human Genome Human Genome Project (HGP)Project (HGP)

15 year project which started in 1990

Project was basically completed in February 2000

HGP GoalsHGP 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 UsesMedical Uses

1. Diagnosis of Diseases

2. Gene Therapy

3. Vaccines

4. Pharmaceutical Products

Forensic UsesForensic Uses

DNA fingerprints for crime solving

DNA identification records

Agricultural UsesAgricultural Uses

1. Animals Increased milk production Increased feed utilization Increased meat production

Injecting DNA into eggInjecting DNA into egg

PharmAnimalsPharmAnimals

Agricultural UsesAgricultural Uses

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

Future Of DNA Future Of DNA TechnologyTechnology

Cloning of higher animals Growth of replacement

tissues and organs Gene therapy to correct DNA

defects ?

Gene TherapyGene Therapy

Summary

Recognize some of the basic strategies and methods of gene manipulation and analysis.

Identify representative examples of the applications of DNA technology.

Be prepared to discuss the implications of genetically modified organisms (GMO’s) on science, technology and society.