11/1/2009 biology: 11.2 human applications genetic engineering human applications genetic...
TRANSCRIPT
11/1/2009
Biology: 11.2 Human Applications Genetic Engineering
Human Applications Genetic Engineering
11/1/2009
Biology: 11.2 Human Applications Genetic Engineering
The 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.
11/1/2009
Biology: 11.2 Human Applications Genetic Engineering
The 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)
11/1/2009
Biology: 11.2 Human Applications Genetic Engineering
The 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.
11/1/2009
Biology: 11.2 Human Applications Genetic EngineeringThe 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.
11/1/2009
Biology: 11.2 Human Applications Genetic EngineeringThe 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.
11/1/2009
Biology: 11.2 Human Applications Genetic EngineeringGenetically Engineered Drugs and
Vaccines: Drugs: Many genetic disorders and
human illnesses occur when the body fails to make critical proteins.
Juvenile 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.
11/1/2009
Biology: 11.2 Human Applications Genetic EngineeringGenetically Engineered Drugs and
Vaccines:
Today, pharmaceutical companies worldwide produce these medically important proteins using bacteria and genetic engineering in combination.
11/1/2009
Biology: 11.2 Human Applications Genetic EngineeringGenetically 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
11/1/2009
Biology: 11.2 Human Applications Genetic EngineeringGenetically Engineered Drugs and
Vaccines:
Vaccines:
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”
11/1/2009
Biology: 11.2 Human Applications Genetic EngineeringGenetically Engineered Drugs and
Vaccines:
Vaccines:
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.
11/1/2009
Biology: 11.2 Human Applications Genetic EngineeringGenetically Engineered Drugs and
Vaccines:
Vaccines:
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.
11/1/2009
Biology: 11.2 Human Applications Genetic EngineeringGenetically Engineered Drugs and
Vaccines:
Vaccines:
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.
11/1/2009
Biology: 11.2 Human Applications Genetic EngineeringGenetically Engineered Drugs and
Vaccines:
Vaccines:
Vaccines made by genetic engineering avoid this danger and are less likely to risk infection to those who are extra-sensitive to the microbes.
11/1/2009
Biology: 11.2 Human Applications Genetic EngineeringDna 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.
11/1/2009
Biology: 11.2 Human Applications Genetic EngineeringDna 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.
11/1/2009
Biology: 11.2 Human Applications Genetic EngineeringDna 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.
11/1/2009
Biology: 11.2 Human Applications Genetic EngineeringDna Fingerprinting:
DNA fingerprinting can also be used to identify the genes that cause genetic disorders, such as Huntington’s Disease and Sickle cell Anemia.
11/1/2009
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?
11/1/2009