1. In this lesson we
examine the use of DNA technology in forensics, medicine, and agriculture (SB2f)
Terms and topics related to DNA Technology:
Biotechnology
cloning
DNA fingerprinting
genetic engineering
Human Genome Project
plasmid
recombinant DNA

2. What is biotechnology?
The use of living organisms to do practical tasks.
Early examples:
The use of microorganisms to make cheese and wine
Selective breeding of livestock and crops
Production of antibiotics from microorganisms
Production of monoclonal antibodies

3. Goal of biotechnology today:
To find practical applications of DNA tecniques for the improvement of human health and food production
Making gene products using Genetic Engineering
Uses in basic research
Medical uses. Diagnosis of disease
Making vaccines and other pharmaceutical products
Forensic uses of DNA such as DNA fingerprinting
Agricultural uses such as making transgenic plants

4. What we can do with DNA and what it can do for us
DNA Technology
What we can do with DNA and what it can do for us

5. DNA TECHNOLOGY
DNA recombination or genetic engineering is the direct manipulation of genes for practical purposes

6. Recombinant DNA technology
Refers to the set of techniques for combining genes from different sources in vitro( in a test tube) and transfering this DNA into a cell so it can be expressed.
These techniques were first developed around 1975 and resulted in the appearance of the Biotechnology industry

7. The tools of recombinant DNA
Plasmids
Restriction enzymes
Gel electrophoresis
PCR ( polymerase chain reaction)

8. Researchers can insert desired genes into plasmids, creating recombinant DNA
And insert those plasmids into bacteria
Bacterium 1
Plasmid
isolated
Cell containing gene
of interest 2
DNA
isolated 3
Gene inserted
into plasmid
Bacterial
chromosome
Plasmid
Recombinant DNA
(plasmid)
DNA
Gene of
interest 4
Plasmid put into
bacterial cell
Recombinant
bacterium 5
Cell multiplies with
gene of interest
Copies of gene
Copies of protein
Gene for pest
resistance
inserted into
plants
Clone of cells
Protein used to make snow form at higher temperature
Figure 12.1
Gene used to alter bacteria
for cleaning up toxic waste
Protein used to dissolve blood clots in heart attack therapy

9. Genetic Engineering
DNA from one species is inserted into another species.
Ex. Human Insulin for diabetics is now made by bacteria cells!

10. Therapeutic hormones
In 1982, humulin, human insulin produced by bacteria
Became the first recombinant drug approved by the Food and Drug Administration
Figure 12.7A

11. Restriction enzymes cut DNA at specific sequences in the DNA
Restriction enzymes = scissors

12. Recombinant DNA Two pieces of DNA cut with the same restriction enzyme will be able to re-combine with each other.

13. Plants 1) Examples of transgenic plants with resistance to viruses…
potatoes, tomatoes, tobacco
2) Examples of transgenic plants with resistance to insects… corn, cotton
3) resistance to herbicides
4) slow down spoilage in tomatoes
5) Extreme example – strawberries that are
resistant to drought, salt, insects, viruses,
cold and frost, and improved taste

14. Animals Bacteria now produce all of the following…
Human growth hormone (HGH) –
Human insulin (replaced cow and pig insulin for human therapy )
Follicle-stimulating hormone
Factor VIII (replaced clotting factors taken from human blood.)

15. Electrophoresis Separation of charged molecules in an electric field.
Nucleic acids have 1 charged phosphate (- charge) per nucleotide. Separation based (mostly) on length: longer molecules move slower.
Done in agarose gel matrix to stabilize.
average run: 100 Volts across a 10 cm gel, run for 2 hours.
Stain with ethidium bromide: bonds between DNA bases and fluoresces orange.
Run alongside standards of known sizes to get lengths

16. Gel electrophoresis sorts DNA molecules by size
Gel electrophoresis sorts DNA molecules by size + –
Power
source
Gel
Mixture of DNA
molecules of
different sizes
Longer
molecules
Shorter
Completed gel
Figure 12.10

17. After digestion by restriction enzymes
The fragments are run through a gel – +
Longer
fragments
Shorter x w y z 1 2
Figure 12.11B

18. Crime
Forensic science is the use of scientific knowledge in legal situations.
The DNA profile of each individual is highly specific.
The chances of two people having exactly the same DNA profile is 30,000 million to 1 (except for identical twins).

19. DNA and Crime Scene Investigations
Many violent crimes go unsolved
For lack of enough evidence
If biological fluids are left at a crime scene
DNA can be isolated from them

20. DNA fingerprinting is a set of laboratory procedures
DNA fingerprinting is a set of laboratory procedures
That determines with near certainty whether two samples of DNA are from the same individual
That has provided a powerful tool for crime scene investigators
Investigator at one
of the crime scenes
(above), Narborough,
England (left)

21. DNA Fingerprinting
1st-The DNA molecule is cut with restriction enzymes
2nd- we have to separate the fragments
This is done by a technique called gel electrophoresis
The DNA is placed on a tray filled with gel through which an electric current runs causing the fragments to move through the gel. The segments separate by how far they move in the gel according to size.
The DNA will form bands corresponding to the bases (and no two people have the same sequence of bases) in the gel which are unique for each individual. This is DNA fingerprinting

22. Example A violent murder occurred.
The forensics team retrieved a blood sample from the crime scene.
They prepared DNA profiles of the blood sample, the victim and a suspect as follows:

23. Does suspect DNA bands match DNA from the crime scene?
Suspects Profile
Blood sample from crime scene
Victims profile

24. DNA fingerprinting can help solve crimes
Figure 12.12B
Defendant’s
blood
Blood from
defendant’s clothes
Victim’s
Figure 12.12A

25. DNA Fingerprinting Gel Electrophoresis
separates pieces of DNA based on size
(after being cut up with restriction enzymes)
Different people will have different banding patterns.
Related individuals will have similar patterns.

26. Solving Medical Problems
DNA profiles can be used to determine whether a particular person is the parent of a child.
A childs paternity (father) and maternity(mother) can be determined.
This information can be used in
Paternity suits
Inheritance cases
Immigration cases

27. Example: A Paternity Test
By comparing the DNA profile of a
mother and her child it is possible to
identify DNA fragments in the child
which are absent from the mother and
must therefore have been inherited
from the biological father.

28. Does this man’s DNA match the DNA of the child?
Mother
Child
Man

29. Cloning organisms
A body cell from one organism and an egg cell from another are fused
The resulting cell divides like a normal embryo

30. Cloning Clone- a member of a group of genetically identical cells
May be produced by asexual reproduction (mitosis)

31. What is cloning? Reproductive cloning
Making an exact copy of a pre-existing or currently existing organism.
Therapeutic cloning
Embryos are grown and stem cells from the embryo are harvested to be used in research to develop treatment for cancer, Alzheimer’s, etc.
Very controversial b/c it kills the embryo in the process.

32. Human Genome Project
Started 1988, finished 2001, the entire sequence of bases in human DNA is now known.
This multi-national effort has led to increased knowledge of …
Human genetic diseases
Gene therapies
Evolutionary relationships
Cellular functions
Cancer genes

33. Gene Libraries
Human genes (and other genes of interest) can be stored inside bacteria cells and viruses which can be saved and grown for use in research.
This may also preserve the genes of endangered or extinct species.

34. Review and Summarize
-use of DNA technology in forensics, medicine, and agriculture (SB2f)
Terms and topics related to DNA Technology:
biotechnology
Cloning
DNA fingerprinting
genetic engineering
Human Genome Project
plasmid
recombinant DNA