Genetic Engineering PowerPoint

lessfrustratedΒιοτεχνολογία

23 Οκτ 2013 (πριν από 3 χρόνια και 7 μήνες)

85 εμφανίσεις

Genetic Engineering

13
-
1 Changing the Living World




Selective Breeding




Hybridization




Inbreeding



Increasing Variation

13
-
2 Manipulating DNA



The Tools of Molecular Biology




DNA Extraction




Cutting DNA




Separating DNA




Using the DNA Sequence




Reading the Sequence




Cutting and Pasting




Making Copies

13
-
3 Cell Transformation



Transforming Bacteria



Transforming Plant Cells



Transforming Animal Cells

13
-
4 Applications of Genetic Engineering



Transgenic Organisms




Transgenic Microorganisms




Transgenic Animals




Transgenic Plants



Cloning










Changing the Living World



Genetic engineering is
the alteration of
genetic

code by artificial means,
and is therefore different
from traditional
selective
breeding
. Only allowing
desired characteristics to
reproduce.


Scorpion poison DNA is
located and inserted into
cabbage DNA. Cabbage
kills caterpillars
(insecticide).

Selective breeding




Hybridization

-

t
he act
or process of mating
organisms of different
varieties or
species

to
create a
hybrid
.


Selective Breeding

Hybridization cont
.


Insecticide resistant crops

Herbicide resistant crops

Vitamin enriched crops


Maize streak virus symptoms
in a commercial maize field in
Klerksdorp,
NorthWest

South
Africa, showing
chlorotic

streaking and deformed cob
development. This farm grew
USA commercial hybrids and
experienced almost total yield
losses.



Selective Breeding



Inbreeding
-
is the
continued breeding of
individuals with similar
characteristics.



Pros
-

maintains
characteristics of the
breed



Cons
-

genetic defects
more common

Increasing Variation



In nature there is a lot
of genetic variation
found in wild natural
populations.


Breeders can increase
variation by inducing
mutations
.


Ex. Belgium Blue

myostatin

muscle
mutation

Increasing Variations with Mutations



Oil eating bacteria
strains created using
mutations

Increasing Variation…. with mutations



Plants have success by
introducing more
chromosomes (mutation).


Polyploidy

is caused by
drugs that double or
triple the amount of
chromosomes. The effect
causes larger and
stronger plants.


Citrus fruits, bananas


Not

successful with
animals


Manipulating DNA



Scientists use their
knowledge of the
structure of DNA and its
chemical properties to
study and change DNA
molecules. Different
techniques are used to
extract DNA from Cells.

Manipulating DNA


Different techniques are
used to :


extract DNA from cells



cut DNA into smaller
pieces



identify the sequence
of bases in a DNA
molecule



make unlimited copies
of DNA.

The Tools of Molecular Biology



Genetic Engineering


making changes in the
DNA code



DNA Extraction


The
cells are opened and
the DNA is separated
from the other cell
parts.

The Tools of Molecular Biology


Cutting DNA


DNA strands are too
long to work with so
scientists use restriction
enzymes to cut DNA
into fragments, at
precise points, on the
DNA strand.


Fits like a “lock and key”
when the DNA is
opened.


The Tools of Molecular Biology


Separating DNA


How DNA is separated
and analyzed


Gel electrophoresis
-
used to compare
genomes or gene
composition of different
organisms or individuals


Using the DNA Sequence



Once DNA is in a
manageable form, it
sequence can be read,
studied, and even
changed. Knowing the
DNA sequence allows
researchers to study
specific genes, to
compare them, and to try
to discover the functions
of different genes and
gene combinations.

Using the DNA Sequence



A chemical dye is added
as a
marker

on bases to
help read the DNA
sequence before
electrophoresis is
started.


Using the DNA Sequence


Cutting and Pasting


“Synthetic” sequences
can be joined to “natural”
sequences using enzymes
that splice DNA together.
It’s like taking a gene from
one organism and
implanting it in another
organism.


Recombinant DNA
is
produced by combining
DNA from different
sources.

Using the DNA Sequence


Making Copies


Scientists need many
copies of a particular
gene to study


Polymerase Chain
Reaction (
PCR
) is a
technique used to make
DNA copies.


Cell Transformation



During transformation,
a cell takes in DNA from
outside the cell. This
external DNA becomes
a component of the
cell’s DNA.


-
ex. Griffith’s
experiment, in 1928,
proved bacteria could
transform DNA


Griffith’s Experiment



Transforming Bacteria



Bacteria can be transformed
using
recombinant DNA


Foreign DNA is joined to the
bacteria’s DNA in the
Plasmid
.


Plasmid’s contain DNA in
the bacteria


-
contains DNA sequences
that
promotes

plasmid
replication


-
Plasmid’s contain genetic
markers making it
easy to
identify

transformed
bacteria.


Transforming Plant Cells



Many plants are
transformed by using
bacteria that insert their
DNA into a plant cell to
produce tumors


1) Scientists turn off the
gene for tumors and
insert recombinant DNA
into the plasmid.


2) Then the recombinant
plasmid can be used to
infect plant cells

Transforming Plant Cells cont…







When plant cell walls are
removed, plant cells in
culture will sometimes take
up DNA on their own.


-
DNA can also be injected
into some plant cells.


Tobacco plant cells
transformed with
reprogrammed virus. Virus
makes
chromophores

to get
energy from the sun to be
used in solar panels.


Transforming Animal Cells



Animal cells can be
transformed in some of the
same ways as plant cells


Egg cells can be injected
w/foreign DNA into the
nucleus


Foreign DNA contains
markers

for identification by
scientists


Genes can be replaced with
new genes


Great for figuring out the
specific functions of genes

Applications of Genetic Engineering



Genetic engineering makes
it possible to transfer DNA
sequences, including whole
genes, from one organism
to another.


-
including plants to animals


-
Enzyme
luciferase
, gene
fireflys

glow, combined with
tobacco plant


Proved that the basic
mechanisms of gene
expression are shared by
plants and animals.

Transgenic Organisms



DNA allows us to construct
organisms that are
transgenic.


Transgenic means that
organisms contain genes
from other species.


Transformed cells can
create whole new
organisms


ex. Glow in dark cats,
transgenic salmon
compared to regular salmon
after one yr.

Transgenic Microorganisms



Transgenic bacteria used
to create important
substances useful in
health and industry


-
reproduce rapidly


-
easy to grow


-
cheap


ex. Insulin, growth
hormone, clotting factor,


Pic
-

chickens that can’t
pass the bird flu



Transgenic Animals











Pic



turned off
myostatin

gene more muscle with
-
out
more food


Used to study genes and to
improve the food supply


Mice given human genes to
mimic our immune systems
to study diseases


Livestock given extra growth
hormone to grow faster


Chickens bacterial resistant
to bacteria that cause food
poisoning


Sheep and pigs make
human milk (proteins)


Transgenic Plants



Important part of the food
supply


Insecticide and herbicide
resistant


Food with more vitamins
(
Vit.A

rice)


May soon produce


-
human antibodies that


can be used to fight


disease


-
Plastics from plants


(maybe)?


-

Food resistant to rot and


spoilage

Cloning



A clone is a member of a
population of genetically
identical cells produced
from a single cell.


Bacteria are easy to clone


Multi
-
cellular
organisms
are more
difficult to clone


Help save endangered
species


1997 William
Wilmut

cloned Dolly