Genetic Engineering notes - Hartland High School

taxmanstrongBiotechnology

Dec 11, 2012 (4 years and 9 months ago)

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GENETIC ENGINEERING


What is it
?



Fast, reliable method for increasing frequency of an allele
in a population



Involves cutting (cleaving) DNA from one organism into
small fragments and inserting fragments into host organism
(of the same or different species
)

Another name for this is
?



Recombinant DNA

recombining fragments of DNA from
different sources


What’s a transgenic organism
?



Contains genes from another organism, uses the foreign
DNA as its own

o

Example glowing tobacco plant

(contains light
-
producing f
irefly enzyme)



3 step process

to produce this:

1.

isolate foreign DNA fragment to be
inserted

2.

attach the DNA fragment to a “vehicle”

3.

transfer the vehicle into a host organism




STEP 1

Restriction enzymes cleave (cut) DNA fragments
out of larger chromosome


o

Res
triction enzymes



DNA cutting enzymes (discovered 1970s)



produced by bacteria



Cut both strands of DNA molecule at certain
sequences (palindromes)



Blunt ends vs. sticky ends

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STEP
2

Vectors transfer DNA


o

Vector = vehicle that carries DNA fragments to host

o

Lo
ose DNA will not become part of host’s
chromosomes w/o a vector



Two Types:



Biological

o

Plasmids

small ring of DNA from

bacterial cell

o

Viral DNA



Mechanical

o

Micropipette

inserted into cell

o

Gene gun

shoots tiny metal ball
coated w/ DNA into cell





STEP
3

Ge
ne splicing & cloning


o

Gene splicing



Plasmid + foreign DNA fragment (both cleaved
with same restriction enzyme)



Join together to reconnect plasmid ring (other
enzymes do this)



Recombined plasmid vector is then placed into
cell of host organism (plant, anim
al, or bacteria)


o

Gene cloning



Just before host cell divides, it copies
recombinant DNA with its own



Identical copies of DNA = gene clones



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o

Animal cloning



Cloned organism = exactly same genes as parent



Single cell from parent is used to make
clone



1980s

& 1990s

mammals were cloned
from
embryos
(mice, sheep, cattle, goats,
rabbits, monkeys)



1997 Dolly!

Sheep clone

o

First mammal cloned from an
adult cell

o

(277
th

attempt)

o



(How to Clone a Mammal pg. 364)