Genetic Engineering and Cloning

About Genetic Engineering1.Genetic engineering:

changing an organism’s DNA to make it more beneficial to humans

a.Genetic engineering has been going on a very long time in the form of selective breeding!

b.Changing a cell’s genome by inserting or removing DNA is very new technology!

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All of the different types of chili peppers are are result of selective breeding – a form of genetic engineering!

Selective Breeding: Creating Plants and Animals for Our Benefit

1.Selective Breeding: Selecting individuals with the desired traits to produce offspring for the next generation

a.Used since the beginning of agriculture to produce superior plant species

b.Used to produce breeds of domestic animals – dogs, horses, cats, sheep, cattle

2. Also called artificial selection

All of the different plants produced from wild mustard by selective breeding!

Hybridization

1.Hybridization: crossing 2 dissimilar, but related organisms

a.Offspring called hybrids

2. Advantages:

a.Usually stronger/hardier than parents – known as hybrid vigor

3. Disadvantages:

a.May promote the loss of native species

1. African catfish (left) grows faster than Thai catfish.

2. Thai catfish (middle) has better tasting flesh than African catfish.

3. Hybrid (right) grows fast & has good tasting flesh.

Genetic Engineering: Recombinant DNA

1.Recombinant DNA: made from pieces of DNA from separate organisms; the pieces stick together

a.DNA from different organisms are “recombined”

2.How recombinant DNA is made:

Transgenic Organisms: Plants1. Transgenic organisms:

any organism that has genes from a different organism inserted into its DNA.

2. Genomes can be produced that could never be produced by naturea. EX: Rice plants and

daffodils usually do not cross pollinate each other in nature

The rice on the right is called golden rice. Its genome contains the gene for producing vitamin A from daffodils. This rice is healthier for people who do not get enough vitamin A in their diets.

DNA Fingerprinting:1. DNA fingerprinting: tool used by

forensics scientists to identify a person using DNA.

2. How it Works:• A sample of the person’s DNA is taken

from blood, semen, bone, or hair.• DNA fragments are placed into a gel &

connected to an electric current• DNA moves through gel; shortest

lengths move fastest & longest lengths move slowest.

• Banding pattern is produced• The banding is unique for each person

– thus called DNA fingerprinting

Was any of the victims blood on the defendants clothing?

Reading DNA Fingerprints

1. DNA fingerprinting is used as evidence in court cases

2. DNA fingerprints are used to support other facts presented to the court

3. A photograph is taken of the bands in the gel & then the bands are compared to the victim’s

Which dog was probably the culprit (dog that bit the person)?

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How Cloning Occurs in Nature

1. Clone: an organism that is genetically identical to another organisma. All of the genes are the same

(identical)2. Examples of cloning that occurs in

naturea. Self-pollinationb. Reproduction in bacteriac. “budding” in spongesd. Regeneration of rays in sea stars

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How Animals are Cloned

Dolly: First cloned mammal

It took scientists 276 attempts to produce a cloned embryo

Dr. Ian Wilmut cloned Dolly

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Born July 5, 1996

How was Dolly Cloned?1. Process is called somatic cell

nuclear transfer a. Nucleus from an adult cell

(A) is transferred to an unfertilized egg that has had its nucleus removed (B)

b. The “fertilized egg” cell is stimulated to divide using electric shock

c. The embryo is implanted into a surrogate mother (C)

2. The “baby” (D) is a clone of the animal that the somatic cell (A) was taken from

A

B

CD

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Uses and Risks of Cloning AnimalsUses:

1. Medical purposes: producing cloned animal models, stem cell research, and for producing medicines

2. Saving Endangered Species

Risks:

1. Somatic cell nuclear transfer is inefficient; only 0.1 to 3 % success rate (Dolly was attempt # 277!)

2. Cloned animals are larger at birth and have larger internal organs; can lead to breathing and blood flow problems

Cloned in 2003 at Texas A & M

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