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Dec 14, 2012 (4 years and 8 months ago)

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Biology: 11.2 Human Applications Genetic Engineering

Human
Applications
Genetic
Engineering

Biology: 11.2 Human Applications Genetic Engineering

T
he Human Genome Project:



The Human Genome Project is
a research project linking 20
labs in six countries.



Teams of scientists in the
project worked to identify and
map all
3.2 billion base pairs

of
all the DNA that makes up the
human genome.



Biology: 11.2 Human Applications Genetic Engineering

T
he Human Genome Project:


One of the most surprising
things about the human genome
is the large amount of DNA
that does NOT encode
proteins.



In fact, only about 1 to 1.5% of
the human genome is DNA that
codes for proteins.
Each human
cell contains about 6 feet of
DNA but less than 1 inch is
devoted to exons.



(recall that
exons

are
sequences of nucleotides that
are transcribed and
translated)



Biology: 11.2 Human Applications Genetic Engineering

T
he Human Genome Project:



Exons are scattered about the
human genome in clumps that
are not spread out evenly
among the chromosomes.



On most human chromosomes,
great stretches of
untranscribed

DNA fill the
chromosomes
between

the
scattered clusters of
transcribed genes.


Biology: 11.2 Human Applications Genetic Engineering

T
he Number of Human Genes:


When they examined the
complete sequence of the human
genome, scientists were surprised
at how few genes their actually
are .



Human cells contain about
30,000

to
40,000

genes.
This is only
about double the number of genes
in a fruit fly.



It is only about one quarter of
the 120,000 genes scientists had
expected to find.



Biology: 11.2 Human Applications Genetic Engineering

T
he Number of Human Genes:


How did scientists make such a
large mistake estimating the
number of genes?



When scientists had counted
messenger RNA (mRNA) they
had found over 120,000. Each
of these can in turn be
translated into a unique
protein.




Scientists had “expected” to
find
as many types of genes
as
their were different types of
mRNA molecules.

Biology: 11.2 Human Applications Genetic Engineering

G
enetically Engineered Drugs and Vaccines:


Drugs:

Many genetic disorders and human
illnesses occur when the body fails to
make critical proteins.



J
uvenile diabetes is such an illness.


The body is unable to control levels of
sugar within the blood because a critical
protein, insulin, cannot be made.



These failures can be overcome if the
body can be supplied with more of the
protein it lacks.


Biology: 11.2 Human Applications Genetic Engineering

G
enetically Engineered Drugs and Vaccines:



Today, pharmaceutical companies
worldwide produce these medically
important proteins using bacteria and
genetic engineering in combination.



Biology: 11.2 Human Applications Genetic Engineering

G
enetically Engineered Drugs and Vaccines:


Today many genetically engineered
medicines are used to treat everything
from burns to diabetes.



Examples include:


Erythropoetin

for anemia


Growth factors
for treating burns,
ulcers


Human Growth Hormone
for growth
defects


Insulin

for diabetes


Interferons

for viral infections and
cancer


Taxol

for ovarian cancer



Biology: 11.2 Human Applications Genetic Engineering

G
enetically Engineered Drugs and Vaccines:

V
accines:



Many viral diseases, such as smallpox and
polio, cannot be treated by existing drugs.
Instead, they are combated by
prevention
through use of vaccines.



A
vaccine

is a solution containing all or
part of a harmless version of a pathogen
(disease
-
causing microorganism).


It is a
weakened version
of the disease;
incapable of causing serious harm”

Biology: 11.2 Human Applications Genetic Engineering

G
enetically Engineered Drugs and Vaccines:

V
accines:



When a vaccine is injected, the immune
system reads the pathogen’s surface
proteins and responds by making defensive
proteins called antibodies.
The immune
system creates a defense system against
this form of the disease.



In the future, if the same pathogen enters
the body,
the antibodies are now there to
combat the pathogen
and stop it’s growth
before it can cause a disease.
The immune
system stays in place so when the flu or
cold strikes in full force, the antibodies
are already there to fight it before it can
grow.

Biology: 11.2 Human Applications Genetic Engineering

G
enetically Engineered Drugs and Vaccines:

V
accines:



Traditionally, vaccines have been prepared
by either killing a pathogenic microbe or
by making the microbe unable to grow.



The disease causing microbe is rendered
into a “weakened form” ;
strong enough to
cause a reaction in the immune system but
not
strong enough to make the taker ill.



Biology: 11.2 Human Applications Genetic Engineering

G
enetically Engineered Drugs and Vaccines:

V
accines:



This ensures that the vaccine itself will
not
cause the disease but only
activate

the
antibodies to form.



With these types of vaccines there is
always
some small danger
for getting sick
as some people are more sensitive to the
vaccine. Their
threshold
is lower.




Biology: 11.2 Human Applications Genetic Engineering

G
enetically Engineered Drugs and Vaccines:

V
accines:



Vaccines made by genetic engineering
avoid this danger and are
less likely
to risk
infection to those who are
extra
-
sensitive

to the microbes.



Biology: 11.2 Human Applications Genetic Engineering

D
na

Fingerprinting
:



Other than identical twins, no two
individuals have the same genetic material.




Scientists use DNA sequencing technology
to determine a DNA fragment’s nucleotide
sequence.

Biology: 11.2 Human Applications Genetic Engineering

D
na

Fingerprinting
:



Because the places a restrictive enzyme
can cut depend on the DNA sequence, the
lengths of the DNA fragments will vary
between any two individuals.



A
DNA fingerprint
is a pattern of dark
bands on photographic film that is made
when an individuals DNA restriction
fragments are exposed to an X
-
ray film.


Biology: 11.2 Human Applications Genetic Engineering

D
na

Fingerprinting
:



Because these bandings are unique to
every individual, they are like fingerprints.



The banding patterns from any two
individuals can be compared to determine
if they are related.



Because fingerprinting can be performed
on a sample of DNA from blood, bone, or
hair;
DNA fingerprinting is used in
forensics as a tool.





Biology: 11.2 Human Applications Genetic Engineering

D
na

Fingerprinting
:




DNA fingerprinting can also be used to
identify

the
genes that cause genetic
disorders
, such as Huntington’s Disease
and Sickle cell Anemia.




Computer Lab:


Use the internet to go online and write a one
paragraph mini
-
report on the following topic:
DO NOT COPY CUT OR PASTE:



How is DNA fingerprinting used in the science
of modern forensics to solve crimes?