DNA Technology - Genetic engineering and all that stuff

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12 Δεκ 2012 (πριν από 4 χρόνια και 8 μήνες)

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Genetic engineering and all that stuff


Eliminate undesirable phenotypic traits in
humans, animals, plants, and microbes



Combine beneficial traits of two or more
organisms to create valuable new organisms



Create organisms that synthesize products
humans need

Figure 8.1.1

Figure 8.1.2






Plasmid Vectors



Restriction Enzymes


Cut DNA at precise locations based upon a specific
target sequence of nucleotides



DNA Ligase


Enzyme that “seals” or ligates DNA pieces together


Eco RI




--
GAATTC
--



--
G


AATTC
--



--
CTTAAG
--



--
CTTAA


G
--



SmaI




--
CCCGGG
--


--
CCC

GGG
--



--
GGGCCC
--


--
GGG

CCC
--




Recognition sequence


Results of cutting


Isolate gene of interest (cut out of genome
with a Restriction Enzyme)



Cut Vector with same R.E. to get compatible
ends



Mix 2 DNAs together and
Ligate

(DNA
Ligase
)



Transform



Screen for successful event



Celebrate



Goal of DNA technology is insertion of DNA
into cell (transformation)



Can use vectors and natural methods of
transformation, transduction, and conjugation



Artificial methods


Electroporation


Protoplast fusion


Injection


gene gun and microinjection



Gel Electrophoresis

Figure 8.7a

RFLPs
restriction fragment length polymorphisms

Figure 8.13

M = mother

F = Father

C = children



both
children show
some bands
with each parent


Reverse transcriptase




DNA synthesis


DNA sequencing





PCR
(Polymerase Chain Reaction)



Large number of identical molecules of DNA are
produced
in vitro



Allows any piece of DNA to be rapidly amplified !



Only minute amounts of DNA are needed !





Heat to ~ 95 degrees to denature the DNA
strands



Cool and elongate with heat tolerant DNA
Polymerase (e.g. Taq polymerase from
Thermus aquaticus
)



Repeat cycle …
Repeat cycle


Repeat cycle


Repeat cycle


Repeat cycle




PLAY

Animation:


Polymerase Chain Reaction


Diagnosis of Disease


Gene Therapy


Vaccines and other Pharmaceuticals


Forensic use


Environmental use (bioremediation)


Agricultural use




* Transgenic animals




* Transgenic plants

Transgenic organisms

Transgenic Sheep

Carrying a human
gene for a human
protein which they
secrete in their
milk. The protein
is then purified
from their milk

Transgenic Golden Rice (High
levels of Beta
-
carotene

used
to make Vitamin A


give the
rice a golden color.

TRANSGENIC PLANT

GMO (genetically modified organism) food
controversy


BT protein is produced by
the bacterium
Bacillus
thuringiensis
. Toxic to some
insects, nontoxic to all other
life forms.



BT corn has the gene
inserted so that the corn
plant makes the BT protein.



Ingestion of BT protein by
the larvae of the European
Corn Borer kills the larvae



The corn plant now has it’s
own defense


Reduced need for pesticides




Greater Yield, etc. etc.




Potential impact on other species


None of any consequence noted….





…but still the GREAT UNKNOWN.


2008 Stats

90% of all soybeans

75% of all corn

65% of all foods on grocery store shelves (soy and
corn syrup are in all sorts of stuff!)


Bananas/potatoes that produce human vaccines


Fish that mature more quickly


Plants that produce plastics


Fruit/nut trees that yield years earlier


Crops that grow where they could not before


Human milk from cows


Etc. etc. etc. etc. etc.

Two featherless chickens peck around in some
grass at the Hebrew University in Rehovot.
Israeli scientists at the Agriculture department of
the university have genetically engineered bare
-
skinned chickens as part of a research project to
develop succulent, low fat poultry that is
environmentally friendly.

(AP)