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Biotechnology
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DNA Technology:
Discussion
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Biotechnology Products
• The use of technology to alter
the genomes of viruses, bacteria,
and other cells for medical or
industrial purposes is called
genetic engineering.
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Biotechnology Products
• Organisms that have had a
foreign gene inserted into them
are called transgenic organisms.
(TRANSferred GENE = TRANS
GENIC)
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DNA technology is changing the
pharmaceutical industry and
medicine
• Therapeutic Hormones Consider human insulin
and human growth hormone (HGH).
• In the United States alone, about 2 million people
with diabetes depend on insulin treatment.
• Before 1982, the main sources of this hormone
were pig and cattle tissues obtained from
slaughterhouses.
• Insulin extracted from these animals is
chemically similar, but not identical, to human
insulin, and it causes harmful side effects in some
people.
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DNA technology is changing the
pharmaceutical industry and
medicine
• Genetic engineering has largely solved this
problem by developing bacteria that synthesize
and secrete actual human insulin.
• In 1982, Human growth hormone was urgently
needed. In 1985, molecular biologists were able
to produce HGH in bacteria.
• Before this genetically engineered hormone
became available, children with a HGH deficiency
had to rely on scarce supplies from human
cadavers or else face dwarfism.
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Human insulin produced by
bacteria
– In 1982, Humulin became the first
recombinant drug approved by the Food
and Drug Administration
Figure 12.7A
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Biotechnology Products
From Bacteria
• Recombinant DNA technology means to
recombine the DNA of an organism to
make it more useful to humans.
• It is used to produce bacteria that
reproduce in large vats to get them to
make a large amount of a particular
protein, such as insulin, growth hormone,
clotting proteins for hemophiliacs, and
hepatitis B vaccine.
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Hepatitis B Vaccine
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Vaccines
• DNA technology is also helping medical
researchers develop vaccines.
• A vaccine is a harmless variant or derivative of a
pathogen (usually a bacterium or virus) that is
used to prevent an infectious disease.
• When a person is inoculated, the vaccine
stimulates the immune system to develop lasting
defenses against the pathogen.
• For the many viral diseases for which there is no
effective drug treatment, prevention by
vaccination is virtually the only medical way to
prevent illness.
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Vaccines
• One DNA technology vaccine is for
the hepatitis B virus.
• Hepatitis is a disabling and
sometimes fatal liver disease, and
the hepatitis B virus may also cause
liver cancer.
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Vaccines
• Smallpox was once a dreaded human
disease, but it was eradicated worldwide
in the 1970s by widespread vaccination
with a harmless variant of the smallpox
virus.
• In fact, the harmless virus could be
engineered to carry the genes needed to
vaccinate against several diseases
simultaneously.
• In the future, one inoculation may prevent
a dozen diseases.
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Video
• Recombinant DNA Technology
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Biotechnology Products
From Bacteria
• Transgenic bacteria
can also help
plants. For
example, bacteria
that live in plants
have genes spliced
in that let them
resist insect toxins;
this protects the
roots of the plants,
too.
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• Bacteria can be
genetically engineered
to degrade a
particular substance,
for instance,
transgenic bacteria
have been produced
which have the
ability to eat oil
after an oil spill.
Biotechnology
Products
From Bacteria
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Biotechnology Products
From Bacteria
• Industry has found that bacteria can be
used as filters to prevent airborne
chemicals from being vented into the air.
• They can also remove sulfur from coal
before it is burned and help clean up toxic
dumps.
• Furthermore, these bacteria were given
“suicide” genes that caused them to selfdestruct when the job is accomplished.
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Biotechnology Products
From Bacteria
• Many major mining
companies already
use bacteria obtain
various metals.
• Genetic
engineering may
enhance ability of
bacteria to extract
copper, uranium,
and gold.
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Biotechnology Products
From Plants
• Plants can also be
genetically
engineered to
make cotton, corn,
soybeans, and
potatoes resistant
to pests because
their cells now
produce an insect
toxin.
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Biotechnology Products
From Plants
• Plants are also being
engineered to produce
human hormones,
clotting factors, and
antibodies, in their seeds.
• One type of antibody made
by corn can deliver a
substance that kills tumor
cells, and another made by
soybeans can be used as
treatment for genital
herpes.
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Genetically modified
organisms are transforming
agriculture
• Scientists concerned with feeding the
growing human population are using DNA
technology to make genetically modified
(GM) organisms for use in agriculture.
• A GM organism (Or GMO) is one that has
acquired one or more genes by artificial
means rather than by traditional breeding
methods. (The new gene may or may not
be from another species.)
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Genetically modified
organisms are transforming
agriculture
• To make genetically modified plants,
researchers can manipulate the DNA of a
single cell and then grow a plant with a
new trait from the engineered cell.
• Already in commercial use are a number
of crop plants carrying new genes for
desirable traits, such as delayed ripening
and resistance to spoilage and disease.
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Genetically modified
organisms are transforming
agriculture
• The most common vector used to
introduce new genes into plant cells is a
piece of DNA from a soil bacterium.
• With the help of a special enzyme, the
gene for the desired trait is inserted into a
plant cell, where it is integrated into a
plant chromosome.
• Finally, the recombinant cell is cultured
and grows into a whole plant.
• If the newly acquired gene is from another
species, the recombinant organism is
called a transgenic organism.
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Genetically modified
organisms are transforming
agriculture
• Genetic engineering is rapidly replacing
traditional plant-breeding programs.
• For example, the majority of the American
soybean and cotton crops are genetically
modified.
• Many of these GM plants have received
bacterial genes that make the plants
resistant to herbicides or pests.
• Farmers can more easily grow these crops
with far less tillage and reduced use of
chemical insecticides.
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Genetically modified
organisms are transforming
agriculture
• Genetic engineering also has great
potential for improving the nutritional
value of crop plants.
• “Golden rice,” a transgenic variety with a
few daffodil genes, produces grains
containing beta-carotene, which our body
uses to make vitamin A.
• This rice could help prevent vitamin A
deficiency—and resulting blindness—
among the half of the world’s people who
depend on rice as their staple food.
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Colored Cotton
• Discovery Channel Video Clip
– On your textbook CD
– Chapter 32
– At the bottom of the page
• “EXTEND YOUR KNOWLEDGE”
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Biotechnology Products
From Animals
• Agricultural researchers are also making
transgenic animals. To do this, scientists first
remove egg cells from a female and fertilize them
in vitro. They then inject a previously cloned
gene directly into the nuclei of the fertilized eggs.
Some of the cells integrate the foreign DNA into
their genomes. The engineered embryos are then
surgically implanted in a surrogate mother. If an
embryo develops successfully, the result is a
transgenic animal, containing a gene from a third
“parent” that may even be of another species.
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Biotechnology Products
From Animals
• The procedure has been used to
produce larger fish, cows, pigs,
rabbits, and sheep.
• Genetically engineered fishes are
now being kept in ponds that offer
no escape to the wild because there
is much concern that they will upset
or destroy natural ecosystems.
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Transgenic Pig
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Biotechnology Products
From Animals
• The goals of creating a transgenic animal
are often the same as the goals of
traditional breeding—for instance, to make
a sheep with better quality wool or a cow
that will mature in a shorter time.
Scientists might, for example, identify and
clone a gene that causes the development
of larger muscles (muscles make up most
of the meat we eat) in one variety of
cattle and transfer it to other cattle or
even to sheep.
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Biotechnology Products
From Animals
• Transgenic animals also have been
engineered to be pharmaceutical
“factories” that produce otherwise rare
biological substance for medical use.
Recently, researchers have engineered
transgenic chickens that express large
amounts of the foreign product in their
eggs. This success suggests that
transgenic chickens may emerge as
relatively inexpensive pharmaceutical
factories in the near future.
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Biotechnology Products
From Animals
• Gene pharming is the use of
transgenic farm animals to produce
therapeutic drugs in the animal’s
milk.
• There are plans to produce drugs for the
treatment of cystic fibrosis, cancer, blood
diseases, and other disorders.
• An anti-clotting medicine is currently
being produced by a herd of goats.
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Pharm Animals
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Biotechnology Products
From Animals
• Animals have been engineered to
produce growth hormone in their
urine instead of in milk.
• Urine is preferable to milk because
only females produce milk, and not
until maturity, but all animals
produce urine from birth.
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Xenotransplantation
• Scientists have begun the process of
genetically engineering animals
to serve as organ donors for
humans who need a transplant.
• We now have the ability to transplant
kidneys, heart, liver, pancreas, lung,
and other organs.
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Xenotransplantation
• Unfortunately,
however, there are
not enough human
donors to go around.
• Fifty thousand
Americans need
transplants a year,
but only 20,000
patients get them.
• As many as 4,000 die
a year while waiting
for an organ.
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Xenotransplantation
• You might think that apes, such as
the chimpanzee or the baboon might
be a scientifically suitable species for
this purpose.
• But apes are slow breeders and
many people object to using apes for
this purpose.
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Xenotransplantation
• In contrast, pigs have been an acceptable
meat source, and a female pig can
become pregnant at six months and can
have two litters a year, each averaging
about ten offspring.
• Ordinarily, the human body rejects
transplanted pig organs.
• Genetic engineering, however, can make
pig organs good for transplantation at
less of a rejection risk.
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Cloning of Animals
• Imagine that an animal has been
genetically altered to serve as an
organ donor.
• What would be the best possible way
to get identical copies of this animal?
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Cloning
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Cloning of Animals
• If cloning of the animal was possible,
you could get many exact copies of
this animal.
• Cloning is a form of asexual reproduction (without sex)
because it requires only the
genes of that one animal.
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Cloning of Animals
• In 1997, scientists at the Raslin
institute in Scotland announced that
they produced a cloned sheep called
Dolly.
• In 1998, genetically altered calves
were cloned in the United States
using the same method.
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Clones
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Clones
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Clone?
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Could GM organisms harm human
health or the environment?
• As soon as scientists realized the power of
DNA technology, they began to worry
about potential dangers.
• Early concerns focused on the possibility
that recombinant DNA technology might
create new pathogens.
• What might happen, for instance, it cancer
cell genes were transferred into bacteria
or viruses?
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Could GM organisms harm human
health or the environment?
• To guard against such rogue microbes, scientists
developed a set of guidelines that were adopted
as formal government regulations in the United
States and some other countries.
• One safety measure is a set of strict laboratory
procedures designed to protect researchers from
infection by engineered microbes and to prevent
the microbes from accidentally leaving the
laboratory.
• In addition, strains of microorganisms to be used
in recombinant DNA experiments are genetically
crippled to ensure that they cannot survive
outside the laboratory.
• Finally, certain obviously dangerous experiments
have been banned.
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Could GM organisms harm human
health or the environment?
• Today, most public concern about possible
hazards centers not on recombinant
microbes but on genetically modified (GM)
crop plants.
• Advocates of a cautious approach fear that
some crops carrying genes from other
species might cause allergies in humans
or create super-weeds that are hazardous
to the environment.
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Could GM organisms harm human
health or the environment?
• Today, governments and regulatory agencies
throughout the world are grappling with how to
facilitate the use of biotechnology in agriculture,
industry, and medicine while ensuring that new
products and procedures are safe.
• In the United States, all projects are evaluated
for potential risks by regulatory agencies such as
the Food and Drug Administration, Environmental
Protection Agency, National Institutes of Health,
and Department of Agriculture.
• These agencies are under increasing pressure
from some consumer groups.
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The Human Genome Project
• The Human Genome Project was a massive
effort to put all of the genes in human
chromosomes into the proper sequence. This
was just finished in 2003.
• Project goals were to identify all the 25,000
genes in human DNA and determine the
sequences of the 3 billion amino acids that make
up human DNA.
• This allows scientists to detect some defective
genes and tailor a treatment plan to the
individual.
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The Human Genome Project
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Gene Therapy
• Gene therapy gives a patient a normal
gene to make up for a faulty gene.
• For example, there is a genetic disease of
the liver that causes it to malfunction and
leads to high levels of blood cholesterol,
which makes the patient subject to fatal
heart attacks at a young age.
• The person is injected with a virus that
contains the normal gene.
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Gene Therapy
• Another example is when fat enzymes are
coated with the missing gene to cure
cystic fibrosis and then sprayed into
patients’ nostrils.
• Anti-cancer genes can also be injected
directly into cancerous tumors.
• Perhaps it will be possible also to use gene
therapy to cure hemophilia, diabetes,
Parkinson disease, or AIDS.
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Diagnosis and Treatment
of Disease
• DNA technology is being used
increasingly in disease diagnosis.
• It is used to determine which genes
are associated with genetic diseases.
• An individual’s gene expression
profile may someday allow
physicians to tailor treatments for
many different disorders.
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Natural Mutation in Fruit Fly
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DNA technology is used
in courts of law
• DNA technology plays an important role in forensic
science, the scientific analysis of evidence for crime scene
and other legal investigations.
• In violent crimes, body fluids or small pieces of tissue may
be left at the crime scene or on the clothes of the victim or
assailant; if rape has occurred, semen may be recovered
from the victim’s body.
• With enough tissue or semen, forensic scientists can
determine the blood type or tissue type using older
methods that test for proteins.
• However, such tests require fresh samples in relative large
amounts.
• Also, because many people have the same blood or tissue
type, this approach can only exclude a suspect; it cannot
provide strong evidence of guilt.
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DNA technology is used
in courts of law
• DNA testing, on the other hand, can identify the
guilty individual with a high degree of certainty
because the DNA sequence of every person is
unique (except for identical twins).
• DNA testing requires only about 1,000 cells.
• In a murder case, for example, such analysis can
be used to compare DNA samples from the
suspect, the victim, and bloodstains on the
suspect’s clothes.
• They provide a DNA fingerprint, or specific
pattern of bands.
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DNA technology is used
in courts of law
• DNA fingerprinting can also be used to
establish family relationships.
• A comparison of the DNA of a mother, her
child, and the purported father can
conclusively settle a question of paternity.
• Sometimes paternity is of historical
interest: DNA fingerprinting provided
strong evidence that Thomas Jefferson or
one of his close male relatives fathered at
least one child with his slave Sally
Hemings.
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DNA technology is used
in courts of law
• Just how reliable is DNA fingerprinting?
• In most legal cases, the probability of two people
having identical DNA fingerprints is between one
chance in 100,000 and one in a billion.
• For this reason, DNA fingerprints are now
accepted as compelling evidence by legal experts
and scientists alike.
• In fact, DNA analysis on stored forensic samples
has provided the evidence needed to solve many
“cold cases” in recent years.
• DNA fingerprinting has also exonerated many
wrongly convicted people, some of whom were
on death row.
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DNA Fingerprinting and the
Criminal Justice System:
Discussion
Defendant’s
blood
Blood from
defendant’s clothes
Victim’s
blood
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Figure 12.12A
Figure 12.12B
Are Genetically
Engineered Foods Safe?
Discussion
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Genetic Profiling:
Discussion
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Medicine’s Wild
Kingdom: Discussion
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Biotechnology
• Dog Genetics
•
http://www.youtube.com/watch?v=K4LtTSBHjk4 (90 mins, start at 15)
• Agriculture Biotechnology Products
•
http://www.youtube.com/watch?v=xZ9Xp-ozZzc (23 mins)
• Biotechnology Products
•
http://www.euronews.com/2013/06/03/biotechnology-to-fight-air-pollution/ (4 mins)
• Biotechnology Techniques
•
http://www.youtube.com/watch?v=A9mqwVZFCRk (14 minutes)
New Cures on the Horizon:
Discussion
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