Ch. 13.3: Genetically Engineered Organisms - Ramsey School District

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12 Δεκ 2012 (πριν από 4 χρόνια και 9 μήνες)

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Ch. 13.3: Genetically Engineered
Organisms

Objectives:


1.
Describe how biologists
genetically modify plants
and animals.

2.
Explain a technique used
to clone animals.

3.
Summarize the GMO
controversy

Vocabulary



G.M.O.


Transgenic


Selective Breeding: Old School Genetic
Engineering



indirect manipulation of DNA


select parents with desirable traits


create “better” individual


oldest way to improve a species


breed


cats, dogs, horses, trees, mice

Selective Breeding: Methods

1. Inbreeding


-

to maintain traits in a population


-

mate parents with similar genomes


-

keeps desirable traits, but increases risks for
undesirable mutations (illness/disease)


2.

Outbreeding (Hybridization)


-

Crossing of distantly related organisms


-

offspring sterile but hardier
(hybrid vigor)


-

ex. Mule, hybrid corn, ligers, etc.

Genetic Engineering

Direct manipulation of DNA


-

cutting and pasting of genes


-

design organisms or create transgenic organisms


Creates a

transgenic organism
-

organism with foreign
DNA or rDNA


Genetically Modified Organism = GMO


Any organism that has acquired genes by artifical
means.


Genetic Engineering: Basic Steps

1.
Isolate desired DNA sequence

Restriction enzymes cut and remove DNA sequences.



2.
Attach desired DNA to a VECTOR


Ligase binds DNA fr. different sources.

Vector = bacteria plasmid or virus that will carry
recombinant DNA to host.




3. Cloning: Host organisms transcribes and translates
desired DNA sequence. Makes MANY COPIES of
enzyme or protein.



Creating Plant GMOs

Applications

Insert genes for:


natural
insecticides


Pesticides


Growing larger
fruits/bigger
flowers


Increase
“nutrient”
content.

Common in soybeans,
rice, corn, wheat

Creating Animial GMOs

Applications

Bigger cattle, leaner meat

More milk production

Better wool production

Have animals produce human proteins to treat disorders.

Animal Clones

Steps

1.
Remove nucleus fr. Egg.

2.
Replace nucleus w/ nucleus (and
chromosomes) fr. a somatic cell

3.
Shock w/ electricity to stimulate
cell division

4.
Place embryo in surrogate female
for gestation.

Sheep, cattle, dogs, cats, pigs,
etc.

Problems: advanced aging and
cancer in clones
.


GMO Controversy

Pros
: New genes can improve crops or animals.

Cons:

Could GMOs be harmful to us?


New allergies? Cancer/illness?

Not many studies.

Not regulated.

Economic concerns

Cloning & Stem Cell Controversy

Stem cells = undifferentiated cells that can turn into
any type of cell (nervous, cardiac, skin, etc.)


Could be used to treat a host of illness/disease


Repair damaged spinal cord tissue


Replace damaged cardiac muscle


Sources: Embryos; Adult cells: bone marrow and cord
blood

(Embryos have the most promise/potential)

Therapeutic Cloning


Use embryonic
stem cells to
create
specialized human
cells.


Goal: Cure
disease


Embryo does not
develop into a
human.

Allowed in U.S. (state by state) w/ restrictions

Reproductive Cloning


Create a human
clone.



Strictly prohibited!