Chapter 13 - Genetic Engineering.pptx - ScienceToGo

sandwichtumtumBiotechnology

Dec 16, 2012 (4 years and 6 months ago)

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Selective breeding


controlled breeding for
desired characteristics; takes advantage of
naturally occurring genetic variation


Fig. 13


1


What are some organisms that are good

examples of selective

breeding?


1. hybridization


breeding technique that

involves crossing dissimilar individuals to

bring together the best traits of both

organisms


2. inbreeding


mating between organisms that

are genetically similar: promotes

preservation of desired characteristics;

decreases

genetic variation



X

Increasing genetic variation can be accomplished
by inducing mutations


1. Bacteria


radiation or chemicals can cause

“beneficial mutations”


Fig. 13
-
3


2. Plants


chemicals that prevent chromosomal

separation lead to polyploidy (What

advantages do these plants have?)


3. Induced mutations can also be used to study

the function of proteins



How do scientists change/manipulate DNA?


1. DNA extraction


remove DNA from the cell


2. DNA cutting


restriction enzymes “cut” DNA

at
very specific
nucleotide sequences


Fig. 13
-
5



Restriction Enzyme
http://www.youtube.co
m/watch?v=yc
-
s
-
WojU5Y&feature=relat
ed

How do scientists change/manipulate DNA?


3. DNA separating


gel electrophoresis uses an

electrical current to separate fragments of

DNA based on size


Fig. 13
-
6



Gel Electrophoresis

http://www.sumanasinc.com/webcontent
/animations/content/gelelectrophoresis.h
tml

Reading the sequence allows the study of specific
genes


Fig. 13
-
7 (Sanger Sequence)


1. Start with a single strand of DNA with

unknown

sequence


2. Mix this strand with DNA polymerase and
a lot

of nucleotides; some of the nucleotides are

“tagged” with dye


3. each time a “tagged” nucleotide is added

replication stops


4. Using gel electrophoresis complementary

DNA strand is “read”



Sanger Sequencing
Videos


http://www.youtube.co
m/watch?v=aPN8LP4Y
xPo&feature=related


http://www.youtube.co
m/watch?v=6ldtdWjD
wes&feature=related



A technique by which any segment of DNA can be
quickly amplified (copied many times)


Fig. 13
-
8


1. DNA is separated and added to a mixture of

nucleotides and enzymes


2. New complementary strands are made


3. Cycle is repeated many times



http://www.youtube.com/watch?v=JRAA4C2OPwg&featur
e=related

PCR Animation


PCR Song
http://www.youtube.com/watch?v=x5yPkxCLads

Some bacteria can take up naked DNA from the

surroundings.

1.
Plasmid


a small, circular, self
-
replicating DNA

molecule separate from the bacterial

chromosome

2.
Assimilated foreign DNA is taken up by the

plasmid

3.
Offspring of the recipient bacterium will carry a
new combination of genes

4.
Genetic marker


a gene that produces a known
protein that can be used to “mark” bacteria that
have taken up foreign DNA





Plant Transformation


Fig. 13
-
10

1.
Plasmids that normally infect plant cells can be
used as carriers of foreign DNA

2.
Whatever gene is taken up is then expressed by
the plant cell

3.
What are some advantages and disadvantages of
this technology?





The bacterium can be
used to introduce
foreign DNA into plant
cells. If the
transformation is
successful, the DNA
will be integrated into
one of the cell’s
chromosomes.

Animal Transformation


Fig. 13
-
11

1.
Eggs cells are large enough to take up foreign
DNA

2.
DNA is inserted manually and enzymes normally
present in the cell to repair DNA help to insert
the foreign DNA

3.
Technique can be sued to study specific functions
of a gene



Transgenic organisms contain genes from another
species; possible because of the universal nature of
the genetic code


Fig. 13
-
12

1.
Microorganisms


easy to grow, divide rapidly,
can be used to produce human proteins

2.
Animals can be used to improve food supply, or
to study effect of human diseases

3.
Plants


genes can be implanted that provide
plants with natural insecticides, or resistance to
various chemicals





This transgenic tobacco
plant, which glows in
the dark, was grown
from a tobacco cell
transformed with the
firefly
luciferase

gene.
The plant illustrates
how DNA from one
organism contains
information that can
specify traits in another
organism.





Cloning


A clone is a lineage of genetically identical
individuals or cells

1.
Basic cloning technique


Fig. 13
-
13 KNOW!!!





In early 1997, Dolly
made headlines as the
first clone of an adult
mammal.



Why did Dolly not look
like her foster mother?



The adult sheep is
Dolly. The lamb is
Dolly’s first offspring.,
called Bonnie. The fact
that dolly was cloned
did
ot

affect her ability
to produce a live
offspring. Why might
it be important for
cloned animals to be
able to reproduce?