Cancer, Stem Cells, and DNA Technology
CHAPTER 12
•Uses of Recombinant DNA Technology
• Recombinant Techniques
– Restriction Enzymes
– Genetic Engineering/Gene Splicing
– Achievements and Dangers of Recombinant DNA Technology
• DNA Fingerprinting and Gel Electrophoresis
• Polymerase Chain Reaction
• Human Genome Project
• Safety and Ethics
• Stem Cells and Cloning
• Cancer Genes, Prevention, and Risk
Restriction Enzymes Cut DNA in Specific Places
• This splicing process can be
accomplished using
restriction enzymes.
– These enzymes cut DNA
at specific nucleotide
sequences.
• These cuts produce pieces of
DNA called restriction
fragments
– That may have “sticky
ends” that are important
for joining DNA from
different sources.
Recombinant DNA Techniques
• Plasmids are small,
circular DNA
molecules that are
separate from the
much larger
bacterial
chromosome.
Genes Can Be Spliced Into Plasmids
Cancer, Stem Cells, and DNA Technology
CHAPTER 12
•Uses of Recombinant DNA Technology
• Recombinant Techniques
– Restriction Enzymes
– Genetic Engineering/Gene Splicing
– Achievements and Dangers of Recombinant DNA Technology
• DNA Fingerprinting and Gel Electrophoresis
• Polymerase Chain Reaction
• Human Genome Project
• Safety and Ethics
• Stem Cells and Cloning
• Cancer Genes, Prevention, and Risk
Recombinant DNA Technology (Genetic Engineering)
Figure 12.2
Applications of DNA Technology: GM Foods
• Today, DNA technology is
quickly replacing traditional
plant-breeding programs.
– In the United States today,
roughly one-half of the corn
crop and over three-quarters
of the soybean and cotton
crops are genetically
modified.
Applications of DNA Technology: GM Foods II
• “Golden rice” has been genetically modified to
contain beta-carotene.
– Our bodies use beta-carotene to make vitamin A.
Applications of DNA Technology: “Pharm” Animals
•
While transgenic plants are used today
as commercial products, transgenic
whole animals are currently only in the
testing phase.
•
These transgenic sheep carry a gene for
a human blood protein.
–
•
•
This protein may help in the
treatment of cystic fibrosis.
While transgenic animals are currently
used to produce potentially useful
proteins, none are yet found in our food
supply.
It is possible that DNA technology will
eventually replace traditional animal
breeding.
Transgenic animals raised
for the purposes of
producting pharmaceuticals
are called pharm animals
Cancer, Stem Cells, and DNA Technology
CHAPTER 12
•Uses of Recombinant DNA Technology
• Recombinant Techniques
– Restriction Enzymes
– Genetic Engineering/Gene Splicing
– Achievements and Dangers of Recombinant DNA Technology
• DNA Fingerprinting and Gel Electrophoresis
• Polymerase Chain Reaction
• Human Genome Project
• Safety and Ethics
• Stem Cells and Cloning
• Cancer Genes, Prevention, and Risk
DNA Fingerprinting and Forensic Science
• DNA technology has rapidly revolutionized the field of
forensics.
– Forensics is the scientific analysis of evidence from crime
scenes.
• DNA fingerprinting can be used to determine whether or
not two samples of genetic material are from a particular
individual.
– It can also show how related two organisms are to each
other by the similarity of their DNA fingerprints
DNA Fingerprinting Generates Banding Patterns Unique to Individuals
1. Collect cells
2. Extract DNA
3. Cut the DNA in
fragments using
the same
restriction
enzyme
4. Separate the
fragments using
gel
electrophoresis
Figure 12.12
The Polymerase Chain Reaction (PCR)
• The polymerase chain reaction (PCR) is a
technique by which any segment of DNA can be
copied quickly and precisely.
– Through PCR, scientists can obtain enough DNA
from even minute amounts of blood or other
tissue to allow DNA fingerprinting.
– A single DNA molecule can be replicated in a test
tube to make 30 million identical copies in a few
hours
– Formerly DNA fingerprinting was not possible
because too little DNA was available at a crime
scene
Polymerase Chain Reaction: DNA Replication in a Test Tube
Exponential Increase in the Number of DNA Molecules each Cycle
Cancer, Stem Cells, and DNA Technology
CHAPTER 12
•Uses of Recombinant DNA Technology
• Recombinant Techniques
– Restriction Enzymes
– Genetic Engineering/Gene Splicing
– Achievements and Dangers of Recombinant DNA Technology
• DNA Fingerprinting and Gel Electrophoresis
• Polymerase Chain Reaction
• Human Genome Project
• Safety and Ethics
• Stem Cells and Cloning
• Cancer Genes, Prevention, and Risk
The Human Genome Project
• In 1990, an international consortium of government-funded
researchers began the Human Genome Project.
– The goal of the project was to sequence the human genome
so scientists could have roadmap for finding genes
Safety and Ethical Issues
•
Safety
–
Moving genes into other organisms
could create hazardous new pathogens
–
Strict laboratory safety procedures have
been designed to protect researchers
from infection by engineered microbes
–
Concerns of GM Foods
•
Crops carrying genes from other
species might harm the
environment.
•
GM foods could be hazardous to
human health.
•
Transgenic plants might pass
their genes to close relatives in
nearby wild areas.
Ethical Issues About Biotechnology
• Should genetically engineered human growth
hormone be used to stimulate growth in HGHdeficient children? To stimulate growth in normal
children, making them tall enough to excel in
basketball or volleyball?
• Should we try to eliminate genetic defects in our
children?
• Advances in genetic fingerprinting raise privacy
issues. Who should have access to your genetic
information?
– Should medical insurance companies know if you
are genetically likely to develop cancer?
Cancer, Stem Cells, and DNA Technology
CHAPTER 12
•Uses of Recombinant DNA Technology
• Recombinant Techniques
– Restriction Enzymes
– Genetic Engineering/Gene Splicing
– Achievements and Dangers of Recombinant DNA Technology
• DNA Fingerprinting and Gel Electrophoresis
• Polymerase Chain Reaction
• Human Genome Project
• Safety and Ethics
• Stem Cells and Cloning
• Cancer Genes, Prevention, and Risk
Therapeutic Cloning and Stem Cells
•
Stem cells are earlystage cells that can
develop into any organ
or tissue of the body.
•
If the right chemical
signals can be added to
stem cells, they can
potentially grow into
replacement organs.
•
Stem cells can be taken
from a fetus after
abortion, from
umbillical cord blood,
or from adult stem cells
(such as those that form
blood cells)
Cloning
• A clone is a genetic duplicate of an existing organism
• Many plants are easily cloned by taking a piece of the plant
and cultivating it
Cloning a carrot
Reproductive Cloning of Animals
• Nuclear transplantation
– Involves replacing nuclei of egg cells with nuclei
from differentiated cells.
– Has been used to clone a variety of animals.
• Scottish researchers cloned the first mammal in
1997.
– Dolly, the sheep, was the product of their work.
• The procedure that produced Dolly is called
reproductive cloning.
The Cloning of Dolly the Sheep
Figure 11.13
Cancer, Stem Cells, and DNA Technology
CHAPTER 12
•Uses of Recombinant DNA Technology
• Recombinant Techniques
– Restriction Enzymes
– Genetic Engineering/Gene Splicing
– Achievements and Dangers of Recombinant DNA Technology
• DNA Fingerprinting and Gel Electrophoresis
• Polymerase Chain Reaction
• Human Genome Project
• Safety and Ethics
• Stem Cells and Cloning
• Cancer Genes, Prevention, and Risk
Cancer Genes (Oncogenes) Result From Damaged Proto-Oncogenes
Unrestricted
mitosis resulting in
tumors (cancer)
Figure 11.18
Cancer Risk and Prevention
• Cancer
– Is one of the leading causes of death in the United
States.
– Breast, lung, colon, skin, and prostate cancers
most common
• Examples of carcinogens
– UV radiation
– Tobacco
– Alcohol
– Certain chemicals like formaldehyde, radon gas
Cancer, Stem Cells, and DNA Technology
CHAPTER 12
•Uses of Recombinant DNA Technology
• Recombinant Techniques
• Restriction Enzymes
• DNA Fingerprinting and Gel Electrophoresis
• Genomics and Proteomics
• Gene Therapy
• Safety and Ethics
•Cancer Genes, Prevention, and Risk
• Stem Cells and Cloning