Genetic Engineering

rheumaticaudienceΒιοτεχνολογία

16 Δεκ 2012 (πριν από 4 χρόνια και 10 μήνες)

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Biotechnology

Selective Breeding


Nonrandom mating to select
for characteristics in parents
that are desired in the
offspring.



Eg. Breeding domestic
animals, domestic crops
-

corn

Genetic Engineering


Direct manipulation of genes
to alter hereditary traits.


Advances in technology have
enabled scientists to use
several different techniques to
study and alter DNA
sequences.

Restriction Enzymes


Discovered
in bacteria.


Enzymes cut the DNA at short,
specific sequences.


Some restriction enzymes cut the
DNA leaving strands that over hang
called “sticky ends”


For
example
: G
A
A

T
T

C




C T
T

A
A

G


Recombinant DNA


Scientists can use sticky ends to join
together segments of DNA from two
different organisms, which is called
recombinant DNA
.



Foreign DNA is put into a
plasmid,
a
circular piece of DNA found in bacteria
.



plasmid

Enzymes cut
plasmid and
foreign DNA

The desired DNA
segment is inserted
into the plasmid.

Foreign DNA

Plasmid with foreign
DNA

Transgenic organisms


The plasmid with the new DNA
can be inserted into a new
organism.


This is creates a
transgenic
organism

Agricultural uses:

genetically modified organisms (GMO)


To give crops disease/ drought
resistance, add nutrients, etc


Flavr

Savr

tomato
: modified to
ripen slower


Golden rice
: rice with added
genes to make Vitamin A

Medical uses: Gene therapy


Genetic diseases are often
caused by
genes that do not
function properly
.


Scientists can add a
functioning
gene

into a plasmid and insert it
into the patient.


Testing treatment for
Cystic
Fibrosis
-

missing one gene.

Gel Electrophoresis


Method used to separate DNA
fragments based on their charge
and size
.

1.
Create an
agarose

gel

with wells
at the top of each lane.

2.
Add
DNA samples
into each well.

3.
Electric current pulls DNA
towards positive end of the gel.

Gel electrophoresis cont.


DNA segments separate by size.


The
longer

segments move
slower so they stay at the top
and the
shorter

segments move
faster and are at the bottom.

Gel electrophoresis cont.


A “
ladder
” is also added in
another lane.


It is made of
DNA fragments
of
known sizes
.


It acts like a
ruler

to measure the
unknown fragment
lengths.


DNA Fingerprinting


A technique used to analyze DNA.
Can compare or identify similarities
between samples of DNA.


Use
enzymes

to cut DNA samples
into segments.


Everyone has different length
segments because of
random
repeated

sequences.


Filter DNA through an
agarose

gel by the process called
gel
electrophoresis.


Compare the pattern of the
DNA bands
.


Matching lengths will appear at
the same
distance
.


Cloning


Remove the
nucleus

from an
egg

cell.


Replace with a
nucleus

from
the individual to be cloned.


The cell will divide into an
embryo
.


Implant embryo into a
surrogate mother
.


The
offspring

that is born will
be a genetic clone (not related
to surrogate mother).


Dolly
-

first cloned mammal

Dolly was the first animal to be
successfully cloned. She was
cloned by Ian Wilmut, Keith
Campbell and colleagues at the
Roslin Institute in Edinburgh,
Scotland.

Born July 5, 1996

Died Feb 14, 2003