1. DNA Technology In laboratory experiments
Genes can be transcribed and translated after being transplanted from one species to another
Called “Recombinant DNA” technology
Can be produced via “Genetic Engineering” (laboratory manipulation)

2. Overview: Understanding and Manipulating Genomes
One of the greatest achievements of modern science has been the sequencing of the human genome, which was largely completed by 2003
DNA sequencing accomplishments
Have all depended on advances in DNA technology, starting with the invention of methods for making recombinant DNA
DNA sequencing animation

3. How can we modify a person’s genome?
Genomics
How can we modify a person’s genome?
Gene therapy - insertion of genetic material into human cells to treat a disorder
Ex vivo therapy – cells are removed for a person altered and then returned to the patient
In vivo therapy – a gene is directly inserted into an individual through a vector (e.g. viruses) or directly injected to replace mutated genes or to restore normal controls over gene activity
Gene therapy has been most successful in treating cancer, to date.

4. Ex vivo gene therapy Genomics 2. Use retroviruses 1. Remove bone
defective gene
retrovirus
normal gene
viral recombinant RNA
viral recombinant DNA
1. Remove bone
marrow stem cells.
2. Use retroviruses
to bring the normal
gene into the bone
4. Return genetically
engineered cells
to patient.
3. Viral recombinant
DNA carries normal
gene into genome.
viral recombinant
RNA
reverse transcription
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

5. DNA Cloning
Concept 20.1: DNA cloning permits production of multiple copies of a specific gene or other DNA segment
To work directly with specific genes
Scientists have developed methods for preparing well-defined, gene-sized pieces of DNA in multiple identical copies, a process called gene cloning

6. 24.3 DNA Technology The Cloning of a Gene
Cloning: Production of many identical copies of an organism through some asexual means.
Gene Cloning: The production of many identical copies of a single gene
Two Ways to Clone a Gene:
Recombinant DNA
Polymerase Chain Reaction

7. Using Restriction Enzymes to Make Recombinant DNA
Bacterial restriction enzymes
Cut DNA molecules at a limited number of specific DNA sequences, called restriction sites

8. Restriction Enzymes and Sticky Ends
Step through animation of cut/splice using EcoRI
Narrated animation

9. Cloning of a Human Gene / Recombinant DNA
Restriction enzymes breaks open a plasmid vector at specific sequence of bases “sticky ends”
Foreign DNA that is to be inserted is also cleaved with same restriction enzyme so ends match
Foreign DNA is inserted into plasmid DNA and “sticky ends” pair up
DNA ligase seals them together
Narrated animation of “Cloning a Gene”

10. 24.3 DNA Technology Polymerase Chain Reaction
Amplifies a targeted DNA sequence
Requires DNA polymerase, a set of primers, and a supply of nucleotides
Primers are single stranded DNA sequences that start replication process
Amount of DNA doubles with each replication cycle
Process is now automated
Narrated animation
Step by step animation

11. 24.3 DNA Technology DNA Fingerprinting
Permits identification of individuals and their relatives
Based on, polymorphisms differences between sequences in nucleotides between individuals
RFLPs : restriction fragment length polymorphisms
Narrated animation
Detection of the number of repeating segments (called repeats) are present at specific locations in DNA
Different numbers in different people
PCR amplifies only particular portions of the DNA
Procedure is performed at several locations to identify repeats

12. DNA Fingerprints
DNA fragments (after digest with restriction enzymes) can be separated through
gel ELECTROPHORESIS
See How:
Animation
Step-by-step electrophoresis
Another walk-through explanation

13. Forensic Evidence
DNA “fingerprints” obtained by analysis of tissue or body fluids found at crime scenes
Can provide definitive evidence that a suspect is guilty or, more specifically, not guilty
Is a specific pattern of bands of RFLP markers on a gel
Defendant’s
blood (D)
Blood from
defendant’s
clothes
Victim’s
blood (V) D
Jeans
shirt V
4 g
8 g
Figure 20.17

14. DNA fingerprinting Can also be used in establishing paternity
Figure: Electrophoresis of PCR-amplified DNA fragments. (1) Father. (2) Child. (3) Mother. The child has inherited some, but not all of the fingerprint of each of its parents, giving it a new, unique fingerprint.

15. 24.3 DNA Technology Biotechnology
Biotechnology uses natural biological systems to create a product or to achieve a goal desired by humans.
“Model Organisms” favored for genetics research

16. Environmental Cleanup
Genetic engineering can be used to modify the metabolism of microorganisms
So that they can be used to extract minerals from the environment or degrade various types of potentially toxic waste materials

17. 24.3 DNA Technology Transgenic Bacteria
Medical Uses: Production of Insulin, Human Growth Hormone, Hepatitis B Vaccine
Agricultural Uses: Bacteria that protects plants from freezing, bacteria that protect plant roots from insects
Environmental: Bacteria that degrade oil (clean up after oil spills), bacteria that remove sulfur from coal

18. Transgenic (GM) Plants
24.3 DNA Technology
Transgenic (GM) Plants
Plants have been engineered to secrete a toxin that kills insects (ex: Bt corn)
Plants have been engineered to be resistant to herbicides (ex: Roundup Ready)
Animation: Gene Transfer in Plants Using a Ti Plasmid

19. Agricultural Applications
DNA technology
Is being used to improve agricultural productivity and food quality
In 2008:
92% of the soybeans and 80% of the corn planted in the United States had been genetically engineered.

20. Genetic Engineering in Plants
Agricultural scientists
Have already endowed a number of crop plants with genes for desirable traits
Bt corn (right)

21. Biotechnology products: Transgenic plants
DNA technology
Biotechnology products: Transgenic plants
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Transgenic Crops of the Future
Improved Agricultural Traits
Disease-protected
Wheat, corn, potatoes
Herbicide-resistant
Wheat, rice, sugar beets, canola
Salt-tolerant
Cereals, rice, sugarcane
Drought-tolerant
Cereals, rice, sugarcane
Cold-tolerant
Cereals, rice, sugarcane
Improved yield
Cereals, rice, corn, cotton
Modified wood pulp
Trees
Improved Food Quality Traits
Fatty acid/oil content
Corn, soybeans
Protein/starch content
Cereals, potatoes, soybeans, rice, corn
Amino acid content
Corn, soybeans
a. Desirable traits
b. Salt-intolerant Salt-tolerant

22. Health focus: Ecological concern about GMO crops
DNA technology
Health focus: Ecological concern about GMO crops
Resistance increasing in the target pest
Exchange of genetic material between the transgenic plant and a related species
Concern about the impact of BT crops on nontarget species (ex: pollinators)

23. GM Animals and “Pharm” Animals
Transgenic animals
Contain genes from other organisms
Sometimes called “chimeras”
Fig 1. transgenic mouse lines expressing GFP known as “green mice.”

24. 24.3 DNA Technology Transgenic Animals
Fish, cows, pigs, rabbits and sheep have been engineered to produce human growth hormone in order to increase size of the animals

25. Transgenic organisms have a foreign gene inserted into their DNA
Have been engineered to be pharmaceutical “factories”
“Pharm” Animals
Figure 20.18
Human breast milk from a cow (2011)

26. Pharmaceutical Products

27.
“Knockout” mice
A number of mice models have been developed: either possessing an inactivated tumor suppressor gene (p53), an activated oncogene (Tg.AC), over-expression of a (human) oncogene (rasH2) or being deficient in nucleotide excision repair (Xpa, de Vries et al., 1995).
These mice models have several advantages:
the number of animals needed for one study is 120 instead of
the duration of the study is 6-9 instead of 24 months leading to less distress of the animals
the transgenic mouse model is considered more discriminating hence improving the accuracy and reliability of human carcinogen identification.

28. Safety and Ethical Questions Raised by DNA Technology
The potential benefits of genetic engineering
Must be carefully weighed against the potential hazards of creating products or developing procedures that are harmful to humans or the environment
Today, much public concern about possible hazards
Centers on genetically modified (GMOs) organisms used as food (allergic reactions, etc)
Gene “escape”