Biotechnology and the
Frontiers of Genetics
What have we learned in
Genetics so far
Traits can be passed from one generation to the
next
 DNA is the material/chemical which is responsible for
heredity
 Traits are actually expressed as proteins/enzymes

– DNARNAProteins (Transcription & Translation)
Mutations can change the DNA; thus new protein
 Evolution / natural selection acts on the changes in
protein; variability comes from mutation

What have we learned in
Genetics so far
What
if that is too slow?
How can humans speed
up the process?
What have we learned in
Genetics so far
Biotechnology!

Biotechnology is the use of living systems
and organisms to develop or make useful
products, or "any technological application
that uses biological systems, living organisms
or derivatives thereof, to make or modify
products or processes for specific use"
BIOTECHNOLOGY: Using Organisms to
Perform Practical Tasks for Humans
In the past…
 Breeders use selective breeding
techniques to pass on desired
characteristics
 Hybridization: offspring are a blend of
parents
 Inbreeding: offspring similar to parents
(higher rate of genetic defects)
Polyploidy
Occurs when chromosomes fail to separate
during meiosis and an organism inherits an
entire extra set of chromosomes
3N = triploid
4N = tetraploid
 Benefits: Makes plants taller and stronger;
good for bananas and citrus fruits
 Risks: Fatal in animals

Today…
Scientists manipulate the living world on a
molecular level to benefit human society
 Use Recombinant DNA Technology
(combines genes from different sources)
 The DNA “code of life” is read and
interpreted the same in all living things!!

Recombinant DNA Technology
In order to recombine DNA from different
sources, we need molecular tools to cut out
and glue back in DNA
 Restriction endonucleases recognize specific
nucleotide sequences, and cut DNA creating
DNA fragments.

– Type I - simple cuts
– Type II – symmetrical cuts from pallindromes
Molecular Scissors
Restriction enzymes
are molecular
scissors
Restriction Enzymes scan the DNA
code
 Find a very specific set of nucleotides
 Make a specific cut

Picking a palindrome
Words that read the same forwards as
backwards
Hannah
hannaH
Level
leveL
Madam
madaM
Racecar
racecaR
Palindromes in DNA sequences
Genetic palindromes
are similar to verbal
palindromes. A
palindromic sequence
in DNA is one in which
the 5’ to 3’ base pair
sequence is identical
on both strands (the 5’
and 3’ ends refers to
the chemical structure
of the DNA).
Each of the double
strands of the DNA
molecule is
complimentary to
the other; thus
adenine pairs with
thymine, and
guanine with
cytosine.
Restriction enzymes recognize and make
a cut within specific palindromic
sequences, known as restriction sites, in
the genetic code. This is usually a 4- or
6 base pair sequence.
Example?
Restriction Enzymes are Enzymes That Cut DNA Only
at Particular Sequences
The enzyme EcoRI cutting DNA at its recognition sequence
Different restriction enzymes have different recognition sequences.
This makes it possible to create a wide variety of different gene fragments.
DNAs Cut by a Restriction Enzyme Can be Joined
Together in New Ways
These are recombinant DNAs and they often are made
of DNAs from different organisms.
Enzyme Site
Recognition
Restriction site
Palindrone
• Each enzyme digests
(cuts) DNA at a
specific sequence =
restriction site
• Enzymes recognize
4- or 6- base pair,
palindromic
sequences
(eg GAATTC)
Fragment 1
Fragment 2
HaeIII
HaeIII is a restriction enzyme that
searches the DNA molecule until it
finds this sequence of four nitrogen
bases.
5’ TGACGGGTTCGAGGCCAG 3’
3’ ACTGCCCAAGGTCCGGTC 5’
5’ TGACGGGTTCGAGGCCAG 3’
3’ ACTGCCCAAGGTCCGGTC 5’
Once the recognition site was found
HaeIII could go to work cutting
(cleaving) the DNA
5’ TGACGGGTTCGAGGCCAG 3’
3’ ACTGCCCAAGGTCCGGTC 5’
These cuts produce what scientists call
“blunt ends”
5’ TGACGGGTTCGAGG
3’ ACTGCCCAAGGTCC
CCAG 3’
GGTC 5’
“blunt ends” and “sticky ends”
Remember how HaeIII produced a “blunt
end”?
EcoRI, for instance, makes a staggered cut
and5’
produces
a “sticky
end”
GAATTC
3’
3’ CTTAAG 5’
5’ GAATTC 3’
3’ CTTAAG 5’
5’ G
AATTC 3’
3’ CTTAA
G 5’
blunt end
sticky end
“sticky ends” are useful
DNA fragments with
complimentary sticky ends
can be combined to create
new molecules which
allows the creation and
manipulation of DNA
sequences from different
sources.
Think about how this could
be used and abused in the
medical field
Restriction Endonucleases
Genetically Modified Organisms
(GMO’s)
An organism with one or more genes
acquired by artificial means
 A TRANSGENIC has DNA from another
species included
 Benefits: Insulin producing bacteria,
herbicide resistant crops, leaner meat, etc.
 Risks: Food allergies, other negative
health effects; introduced species or
“superweeds”

Transgenic Rice
Bovine Somatotropin
Risk and Regulation

Questions
– How do we measure the potential risks of
genetically modified crops ?
– Is eating genetically modified food dangerous
?
– Are genetically modified crops harmful to the
environment ?
– Should we label genetically modified foods ?
Animal Cloning
Benefits: Faster mass production of
animals with desired characteristics;
Reproduction of a GM animal
 Risks: Loss of life; Ethical concerns,
expensive

DNA Fingerprinting
Gel Electrophoresis is the technique used
to create DNA fingerprints
 Restriction enzymes chop up different
DNA
 Can compare DNA from multiple subjects
to solve a crime, determine paternity, etc.

DNA Fingerprinting

DNA fingerprinting
– Because two individuals most likely will not
have the same DNA and same number of sites
where restriction enzymes cut DNA, DNA
fingerprints can be used in criminal
investigations.