Download Recombinant DNA and Genetic Engineering

Recombinant DNA and
Genetic Engineering
Chapter 12
Goals for this chapter
 Have a general understanding of
Genetic Engineering and Biotechnology
 Be able to form an opinion that is based
on fact or emotion
 And recognize the difference
Focus our attention on
 Genetic Improvement of Crop Plants
 Other possible topics
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Genetic improvement of animals
Genetic improvement of Humans
Stem cell therapy
Forensics
Historical research
And on and on
What is Biotechnology
 Definitions
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Biotechnology
Genetic Engineering
Recombinant DNA
Transgenic or GMO
Biotechnology
 Genetic Improvement of plants and
animals
 This would include the activities of Plant
Breeders
 And plant breeders are really nice people
Genetic Changes
 Humans have been changing the genetics
of other species for thousands of years
 Artificial selection of plants and animals
 Natural processes also at work
 Mutation, crossing over
Traditional plant breeding
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Select parents
Cross and generate variable offspring
Select the desired types
Test - Test - Test
Multiply
Release
7 to 15 years
Norman Borlaug
 Nobel Peace Prize
 1970
 The Green Revolution

http://nobelprize.org/peace/laureates/
1970/borlaug-lecture.html
Barbara Mclintock
 Transposons
 1983 Nobel Prize
in Medicine
Genetic Engineering
 Modern Biotechnology - which uses the
knowledge of DNA to manipulate the genetic
makeup of an organism
 Recombinant DNA - take a gene from one
organism and place it into another organism
 Transgenic or GMO - an organism that
contains DNA from another organism
Would You Eat a
Genetically Engineered
Food?
Most GMO’s are Plants
 34% of Corn
 71% of Cotton
 75% of soybeans
Silk is Soy
Why no GMO
Until recently the terms Genetically Modified
Organism (GMO), GMO-Free and Non-GMO
were used to help identify foods that
contained genetically altered ingredients.
 These terms are no longer recognized by the
Food and Drug Administration (FDA) and
therefore cannot be used on food packaging.
What about Tostito’s
 Or Pepsi
 Or Coke
 Or CapN Crunch???
How to Manipulate DNA
in the Lab
Examples of Transformation
 Natural Systems
 Bacteria
 Viruses
Bacterium
bacterial
chromosome
plasmid
Transformation with DNA fragment
bacterial
chromosome
DNA
fragments
virus
viral DNA
2 Virus enters host cell.
host cell
3 Virus releases its DNA into
host cell; some viral DNA (red)
may be incorporated into the
host cell’s DNA (blue).
host cell DNA
1 Virus attaches to
susceptible host cell.
viral DNA
“hybrid virus”
6 Host cell bursts, releasing
newly assembled viruses.
when “hybrid viruses” infect a
second cell, they may transfer
genes from the first cell to the
second cell.
viral proteins
4 Viral genes encode synthesis
Of viral proteins and viral gene
Replication. Some host cell DNA
May attach to replicated viral
DNA (red/blue).
5 New viruses assemble; host
cell DNA is carried by “hybrid
viruses.”
GE Tool Box
Based on the Central Dogma and the fact that in
virtually organisms the CODE is perfectly conserved
almost
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Restiction Enzymes
Cloning Vectors
cDNA Cloning
Reverse
Transcriptase
 PCR
 Gene Library
(Isolation)
 Transformation of
Plants
Amplifying DNA
 Fragments can be inserted into
fast-growing microorganisms
 Polymerase chain reaction (PCR)
Polymerase Chain Reaction
 Sequence to be copied is heated
 Primers are added and bind to ends of
single strands
 DNA polymerase uses free nucleotides
to create complementary strands
 Doubles number of copies of DNA
Polymerase
Chain
Reaction
Double-stranded
DNA to copy
DNA heated to
90°– 94°C
Primers added to
base-pair with
ends
Mixture cooled;
base-pairing of
primers and ends
of DNA strands
Stepped Art
DNA polymerases
assemble new
DNA strands
Fig. 16-6, p. 256
Polymerase
Chain
Reaction
Mixture heated again;
makes all DNA
fragments unwind
Mixture cooled; basepairing between
primers and ends of
single DNA strands
Stepped Art
DNA polymerase
action again
doubles number of
identical DNA
fragments
Fig. 16-6, p. 256
Fig. 16-7, p.247
DNA Fingerprinting
Guilty or Innocent
8 side-by-side (tandem) repeats
of the same 4-nucleotide sequence,
power supply
pipetter
DNA bands
�
�
(not yet visible)
gel
gel
wells
nylon
paper
DNA samples are pipetted into wells
(shallow slots) in the gel. Electrical current
is sent through the gel (negative at end
with wells, positive at opposite end).
Electrical current moves DNA
segments through the gel. Smaller
pieces of DNA move farther toward the
positive electrode.
Gel is placed on special nylon
�
�
paper.
Electrical
current drives
DNA out of gel onto nylon.
solution of DNA probes (red)
nylon paper
Nylon paper with DNA is bathed in a solution of labeled DNA probes (red) that
are complementary to specific DNA segments in the original DNA sample.
Complementary DNA segments are labeled by probes
(red bands).
power supply
pipetter
�
�
gel
wells
�
�
DNA samples are pipetted into wells
(shallow slots) in the gel. Electrical current
is sent through the gel (negative at end
with wells, positive at opposite end).
�
�
DNA bands
(not yet visible)
�
Electrical current moves DNA
segments through the gel. Smaller
pieces of DNA move farther toward the
positive electrode.
�
gel
�
�
�
Gel is placed on special nylon
paper. Electrical current drives
DNA out of gel onto nylon.
�
nylon
paper
solution of DNA
�
� probes (red)
nylon paper
�
�
Nylon paper with DNA is bathed in a solution of labeled DNA probes (red) that
are complementary to specific DNA segments in the original DNA sample.
�
�
�
�
Complementary DNA segments are labeled by probes
(red bands).
Penta D
CSF
D16
D7
D13
D5
Number of repeats
STR name
D16: an STR on chromosome 16
DNA samples from
13 different people
Penta D
CSF
D16
D7
D13
D5
Number of repeats
STR name
Number of repeats
D16: an STR on chromosome 16
DNA samples from
13 different people
Genetic Engineering
Transformation of Plants
 Genes are isolated, modified, and
inserted into an organism
 Made possible by recombinant
technology
 Cut DNA up and recombine pieces
 Amplify modified pieces
Process
Board Diagram
Corn Transformation with RR gene
From a bacteria or petunia
Hypothetical Situation
Corn Cotton and Alfalfa
Roughly 400 million people in the world today are at risk of Vitamin A
deficiency, which already affects 100-200 million children. Vitamin A
deficiency causes various health problems, including blindness. Because
rice is an important crop, eaten by almost half of the people in the world,
the Rockefeller Foundation and the European Union funded research
into varieties that might offer global health benefits.
It may now be possible, thanks to agricultural biotechnology, to make rice
and other crops into additional sources of Pro-Vitamin A. With
Monsanto's help, the developers of "Golden Rice" and mustard with more
Pro-Vitamin A should one day be able to deliver their gift of better
nutrition to the developing nations of the world through staple crops
readily available to poor and vulnerable populations
Imagine sharing science to help others develop crops that could help
reduce Vitamin A deficiency, a leading cause of blindness and infection
among the young.
Imagine innovative agriculture that creates incredible things.
Discussion
 Debate the Merits or Dangers of Golden
Rice.
 Group One - Make your case in front of
Congress to obtain money to distribute
this rice (as rice seed) to the farmers of
Southeast Asia and Africa
 Group Two - Argue against this.
You be the judge
 With your pocket book
 Or your advocacy
Ethical Issues
 Who decides what should be “corrected”
through genetic engineering?
 Should animals be modified to provide
organs for human transplants?
 Should humans be cloned?