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How can we cause an organism to possess a trait of another organism?
Since ALL living things use DNA as their genetic material, it is possible to insert DNA from one species to another, either through a cross if the organisms are of the same species, or through recombinant DNA if the organisms are dissimilar.
Manipulating DNA
• Scientists are now able to manipulate, or handle and change, DNA within organisms.
• They are able to examine DNA on an entirely new level because of increases in technology.
• They are able to change DNA or extract DNA from one organism and place it in another. However, this is not always successful.
Genetic Engineering• Genetic engineering the
process of replacing specific genes in an organism in order to ensure that the organism expresses a desired trait. – Accomplished by taking
specific genes from one organism and placing them into another organism.
Gene Map
Genetic engineering occurs when scientists know exactly where genes occur on chromosomes. A gene map shows this.
Human Genome Project• Genome refers to
all the genetic material in an organism.
• The Human Genome Project that mapped the DNA sequence of human genes is useful in identifying genes for specific traits.
CloningIn cloning, an identical copy of a gene or an entire organism is produced. Cloning brings benefits but may also result in genetic disorders or health problems.
Gene Therapy
In gene therapy, scientists insert normal genes into absent or abnormal genes. Once inserted, the normal gene begins to produce the correct protein or enzyme, eliminating the cause of the disorder. However, gene therapy has had limited success because the hose often rejects the injected genetic material.
Results of Genetic Engineering
• Plants that make natural insecticides, are higher in protein, or spoil more slowly.
• Animals that are bigger, are faster growing, or are resistant to disease.
• Bacteria that produce hormones such as human insulin or human growth hormones.
• In humans, it is theoretically possible to insert copies of normal genes into the cells of people with different genetic disorders.
Let’s Think…
• Why would you want to selectively breed an organism?
• How is selective breeding done?
• What are some organisms that are often products of selective breeding?
Selective Breeding
• Selective breeding is the method of artificially selecting and breeding only organisms with a desired trait to produce the next generation. Almost all domesticated animals and most crops have been selectively bred.
The puggle is NOT considered to be a breed of dog.
Pug Beagle
Puggle
***What would have to be done to make the puggle a breed?***What evidence would we have that a new breed had been created?
Canis familiarisCanis familiaris
Canis familiaris
Inbreeding
• In order to keep lines of breeds pure, breeders will often interbreed their organism, called inbreeding. While the line will stay pure, it may also result in many genetic disorders and problems. The drawback being recessive gene defects often show up.
HybridizationA form of Selective Breeding
Tiger + Lion = Liger
http://members.diaryland.com/edit/adclick.phtml?a=709142448 http://www.eriksaunders.com/archive.FEB05.htm
Top 10 Animal HybridsPanthera tigris x Panthera leo
K: AnimaliaP: ChordataC: MammaliaO: PrimatesF: HomindaeG: PanS: troglodytes
K: AnimaliaP: ChordataC: MammaliaO: PrimatesF: Homindae G: ?S: ?
http://www.primarilyprimates.org/videos/index.html
They say that the closest relative of humans is the chimpanzee. Would a hybrid be possible?
K: AnimaliaP: ChordataC: MammaliaO: PrimatesF: HominidaeG: HomoS: sapiens
Recombinant DNA
• Faster than selective breeding.• Only 1 generation needed.• More predictable results than
selective breeding.• Can transfer traits from species that
are completely unrelated.
What can be done with Recombinant DNA ?
These fluorescent Zebrafish contain DNA of a sea anemone to cause their glow.
Corn earworms frequently destroy corn crops. GM Corn can be made to produce a protein that kills these insects—corn that makes its own pesticide.
GM chickens in Israel can be grown featherless, but more meaty—a benefit to farmers.
“Genetically Modified Foods”“Transgenic Organisms”
GOOD: can increase world food supply—can make farming easier
BAD: can aggravate food allergies—too much use of antibiotics— risk of pesticide resistance
“ORGANIC” food products that have not had any genetic modification.
Frankenfoods?
Are organic foods healthier? Should they cost more?Is there any danger posed by eating GM foods?Should food labels indicate the GM of the food
products?
Guess What’s for Dinner!!
