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12 Δεκ 2012 (πριν από 4 χρόνια και 11 μήνες)

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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


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.

Restriction Enzymes Cut DNA in Specific Places

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

Figure 12.2

Recombinant DNA Technology (Genetic Engineering)


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


“Golden rice” has been genetically modified to
contain beta
-
carotene.


Our bodies use beta
-
carotene to make vitamin A.

Applications of DNA Technology: GM Foods II


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.

Applications of DNA Technology: “Pharm” Animals

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

Figure 12.12

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

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.


Should genetically engineered human growth
hormone be used to stimulate growth in HGH
-
deficient 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?

Ethical Issues About Biotechnology

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 early
-
stage 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.

Figure 11.13

The Cloning of Dolly the Sheep

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

Figure 11.18

Cancer Genes (Oncogenes) Result From Damaged Proto
-
Oncogenes

Unrestricted
mitosis resulting in
tumors (cancer)

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