Genetic Engineering (GE)

viewkickapooBiotechnology

Dec 12, 2012 (4 years and 4 months ago)

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Biology

Notes

Dr. Hensley

& Mrs. Ingram


May 1, 2012

Genetic Engineering

Hybridization



Crossing two organisms to get best traits; Example: Cross a pretty horse with
a fast horse to get a pretty, fast horse.

Inbreeding



Breeding population over and over

and limiting gene pool; Ex: Puppy Mills

Genetic Engineering (G.E.)



Changing DNA in an organism on purpose by lab procedures

“Biotechnology”
-

Use knowledge of DNA (structure/chemical properties)


4 Techniques in G.E.


1.

Extract DNA


cut open cells and se
parate out DNA from everything else

2.

Cut DNA into pieces


Use restriction enzymes to cut DNA at specific points making
segments like puzzle pieces


3.

Separate and sequence the DNA pieces using gel electrophoresis

to find the order


4.

Make lots of copies of
DNA through PCR (Polymerase Chain Reaction)






Gel Electrophoresis of DNA




Size and charge effect the separation of the DNA



Smaller segments move farther down the gel



More negative charged segments are attracted to the positive end and therefore
move

farther down the gel

Reading Sequence



Read from bottom to top!!!!





Reading the S
equence:

In order to sequence a piece of DNA, you need to mix the
following ingredients in a test tube:

1.

Piece of single stranded DNA ; we want to find order of bases

2.

DNA
Polymerase

3.

4 Nucleotides

4.

Add tagged (labeled) nucleotide so you can see it




Must add a tag
: Tagging does 2 things:

1.

Stops DNA polymerase from adding any more nucleotides

2.

Makes DNA visible by being colored (each nucleotide is color coded), or radioactive a
nd
will make a photograph on photographic paper.

So, for example, if the first nucleotide in the sequence is on “A” and if an “A” is tagged, it
won’t be added to, and will show up in the A column in the gel.

PCR Polymerase Chain Reaction



Reproducing more

DNA for testing



Add all ingredients:
DNA polymerase

(enzyme to build DNA)
, nucleotides
, and
primer
RNA

tells where DNA polymerase should start

1.

Heat DNA (Break Hydrogen bonds) add heat resistant polymerase from Archaebacteria

2.

Cool Down


allows primer to
attach

3.

DNA polymerase makes a copy

4.

Repeat process to make lots of copies fast ( 1strand

2 strands


4 strands

8 strands)

Three Reasons to Sequence DNA

1.

To study

DNA
sequences

2.

Compare genes/genomes

3.

Find function of genes

Recombinant DNA



DNA molecule that
has DNA from another source; pieces of artificial
DNA joined to natural DNA

Transformation



Process to make recombinant DNA

Transgenic Organism


Organism that has been transformed
; has DNA from another organism

Plasmids
-

Circular piece of DNA in bacteria

or that can be taken up by bacteria


2 Reasons plasmids are useful for DNA transfer

1.

Know its sequence

2.

Has genetic marker which tells when transfer is successful

4 Steps in Transforming DNA

1.

Foreign DNA joined to plasmid by using resistance enzymes

2.

Some
bacteria are successful (transformation)

3.

Treat with antibiotics

4.

Ones successful grow because they carry the gene for resistance




Transform Plants, Bacteria, or Animals



Example: Glow
-
in
-
the
-
Dark tobacco plants

Transforming Plants:



Bacteria that normally

cause cancer in plants


turn off the cancer gene and put in gene
we want to go in and allow gene to infect plant like normal
.



Remove cell wall, plant picks up DNA on its own



DNA can also be injected directly into plants



Both will develop into adult plant
s

Transforming Animals:



Eggs that are large enough, DNA injected directly into nucleus (still need marker gene)



Example: “Knock out” genes


determines what gene does


disrupting the sequence or
by removing it, scientists look at what protein is no longer

made and say “that gene, when
it worked, must have made Protein X and therefore determine the gene’s function that
way.

Transgenic Plants
-

Natural resistance to pests/fungi/disease, vitamins in rice means no
insecticide needed, plants resistant to rot
, h
uman antibodies

Transgenic Animals



Chickens resistant to Salmonella, mice with human immune system,
leaner meat in animals, pig or sheep milk with human proteins














Cloning


When you produce an organism with identical cells as the original cell; NOT
Transgenic organism since you are using DNA from same species and not different organism

Steps of Cloning

1.

Nucleus from egg cell is removed

2.

Fuse that nucleus with a donor egg (adul
t cell) with electricity

3.

Divide normally

4.

Embryo is placed in uterus of foster mother