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.
IdentificationIdentification
Screening the altered cells for the desired gene
Ex: Antibiotic sensitivity or the expression of a “new” trait (color, glowing etc.)
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
Agricultural UsesAgricultural Uses
1. Animals Increased milk production Increased feed utilization Increased meat production
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 ?