Genetic Engineering.ppt

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14 Δεκ 2012 (πριν από 4 χρόνια και 11 μήνες)

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Genetic
Engineering


Genetic Engineering

Altering the genotype of an
organism by:

1. adding new DNA to it, or

2. changing its DNA


Recombinant DNA
Technology

Basic technique:

1. Cut two DNA molecules
into fragments

2. Join them in the desired
combination


Restriction Enzymes

Enzymes (nucleases) that
cut DNA at a specific
sequence:
The restriction site


Restriction enzymes

Hundreds have been
discovered

Naturally exist in bacteria
and are named after the
species they are found in


Restriction Sites
Eco
RI:
Hind
III:
GAATTC
AAGCTT
CTTAAG
TTCGAA



Restriction Enzymes

Cut DNA and produce
RESTRICTION FRAGMENTS
of different sizes



Cutting DNA with certain
RE will result in “sticky
ends” on the DNA
molecule




Plasmids

Molecule of DNA separate
from bacterial chromosome

Small and circular

Used as genetic

VECTORS




Plasmid Vectors

Scientists insert DNA
gene into vector

Vector is transferred into
bacterial cell where it
replicates


Importance of
E. coli

The
“laboratory
mouse” of
bacteria

Used in
genetic
engineering


PROCEDURE:
Cloning a gene
1.
Cut around the DNA
sequence with RE’s
2.
Insert the DNA fragment
into a plasmid vector


PROCEDURE:
Cloning a gene
3.
Put the plasmid into an
E.coli
cell by
transformation
4.
Plasmid replicates and
inserted gene is expressed
by every new cell


Cloning


Why do we clone genes?

Production of drugs

To give desired properties
to crops

Produce transgenic
organisms


Transgenic organisms

Gene from
Arctic char
fish inserted
into tomato
= Frost-
resistant
tomato



http://filebox.vt.edu/cals/c
ses/chagedor/97microbes.
html