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Ch. 11 Genetic Technology
Selective Breeding

From ancient times, breeders have chosen plants
and animals with the most desired traits to serve as
parents of the next generation.

Breeders of plants and animals want to be sure that
their populations breed consistently so that each
member shows the desired trait.

Increasing the frequency of desired alleles in a
population is the essence of genetic technology.
Inbreeding develops pure lines

Inbreeding is mating
between closely related
individuals. It results in
offspring that are
homozygous for most traits.

can bring out harmful,
recessive traits because
there is a greater chance
that two closely related
individuals both may carry a
harmful recessive allele for
the trait.
•Horses and dogs are two
examples of animals that
breeders have developed as
pure breeds.
Hybridization

hybrid is the offspring of
parents that have
different forms of a trait.

In the case of plants, it
can lead to new
“varieties” of existing
plant types

Sometimes two
different species are
mated to create the
desired
characteristics
 Only can occur
between closely
related species
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
Ligers are a cross
between a male lion
and a female tiger.
They can grow to 10
feet long.
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
Beefalo are a cross
between American
Bison and beef
cattle.
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
A Zeboid is a cross
between a zebra
and some other
equine species.
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Human Hybrids?

There is controversy
surrounding human
hybrids.
 Is it possible? Has it
happened?

Several states have
actually banned
people from
intentionally or
knowingly creating a
human animalhybrid. (Arizona,
Louisiana,
Oklahoma, and
Ohio)
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
http://www.npr.org/templates/story/story.
php?storyId=128427672
The Ivanov Experiments
Ilya Ivanov was a Russian scientist who
attempted to create a human-chimp
hybrid from 1924-1930
 All attempts were unsuccessful
 In 1930 he fell out of favor with the
government and was exiled to the
Kazakh SSR where he died two years
later.


Other rumored “Humanzees” include
reports of experiments in China in the
1960’s and Florida in the 1920’s
What would a “Humanzee” look
like?
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decompressor
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Oliver’s Story
The previous photo is of Oliver
 He was thought to possibly have been a
human-chimp hybrid
 Later genetics testing found him to have
48 chromosomes (chimp #)
 So he was a chimp!

http://news.nationalgeographic.com/new
s/2003/04/0414_030314_strangeape.ht
ml
 http://karlammann.com/gallerybondo.html

Genetic Engineering

Genetic engineering is a faster and more
reliable method for increasing the frequency
of a specific allele in a population
 This method involves cutting—or cleaving—
DNA from one organism into small fragments
and inserting the fragments into a host
organism of the same or a different species.

You also may hear genetic engineering
referred to as recombinant DNA technology
 Recombinant DNA is made by connecting or
recombining, fragments of DNA from different
sources.
Transgenic organisms contain
recombinant DNA

Plants and animals that contain
functional recombinant DNA from an
organism of a different genus are known
as transgenic organisms because they
contain foreign DNA.
recombinant DNA
Enzymes are used to “cut and paste”

Steps involved:
Isolate a desired gene using
restriction enzymes:are bacterial proteins
that have the ability to cut both strands of the DNA
molecule at a specific nucleotide sequence.(the
scissors doing the cut
DNA ligase “pastes” the DNA fragments
together (the glue)
 The result is recombinant DNA
Restriction enzymes cleave DNA


The same sequence of
bases is found on both DNA
strands, but in opposite
orders. GAATTC
CTTAAG

This arrangement is called a
palindrome. Palindromes
are words or sentences
that read the same forward
and backward.

form sticky ends:
single stranded ends
that have a tendency to
join with each other (
the key to recombinant
DNA
Vectors transfer DNA

vector is the means by which
DNA from another species
can be carried into the host
cell.

may be biological or
mechanical.

Biological vectors include
viruses and plasmids. A
plasmid, is a small ring of
DNA found in a bacterial cell.
Plasmids
Vectors transfer DNA

Two mechanical vectors carry foreign DNA
into a cell’s nucleus
 One, a micropipette, is inserted into a cell; the
other is a microscopic metal bullet coated
with DNA that is shot into the cell from a gene
gun.
1..Isolate DNA
from two sources
Gene cloning
Plasmid




Bacteria take the
recombinant plasmids
and reproduce
This clones the
plasmids and the genes
they carry
Clones are genetically identical
copies.
3. Mix the DNAs;
they join
by base-pairing
Recombinant
DNA
plasmid
– Products of the gene can
then be harvested
The process of cloning a
human gene in a bacterial
plasmid can be divided into
Bacterial clones
six steps.
carrying many
copies of the
human gene
Human
cell
2.Cut both
DNAs with
the same
restriction
enzyme
4.Add DNA ligase
to bond the DNA
covalently
5. Put plasmid
into bacterium
6.Clone the
bacterium
Cloning of animals


Scientists are perfecting
the technique for
cloning animals
http://learn.genetics.uta
h.edu/content/tech/cloni
ng/clickandclone/
Risks To Cloning Animals
High failure rate
 LOS (Large Offspring Syndrome)
 Telomeric Differences (Aging Shortens
Telomeres, clones can have longer or
shorter telomeres)
 Abnormal Gene Expression Patterns
 Ethical Issues

Polymerase chain reaction
(PCR)

method is used to
amplify DNA sequences

The polymerase
chain reaction
(PCR) can quickly
clone a small
sample of DNA in a
test tube
Initial
DNA
segment
Number of DNA
molecules
Sequencing DNA

millions of copies of a double-stranded DNA fragment are
cloned using PCR. Then, the strands are separated from each
other.

The single-stranded fragments are placed in four different test
tubes, one for each DNA base.

Each tube contains four normal nucleotides (A,C, G,T) and an
enzyme that can catalyze the synthesis of a complementary
strand.

One nucleotide in each tube is tagged with a different
fluorescent color.

The reactions produce complementary strands of varying
lengths.

These strands are separated according to size by gel
electrophoresis producing a pattern of fluorescent bands in the
gel.

The bands are visualized using a laser scanner or UV light.
Gel Electrophoresis sorts DNA molecules by
size

Separation technique: separates DNA by size and charge
 1.Restriction enzymes
– cut DNA I into fragments

2. The gel
– Wells made at one end. Small amounts of DNA are placed in the wells
3. The electrical field
gel placed in solution and an electrical filed is set up with one neg. (-)
& one pos. (+) end
4. The fragments move
negatively charged DNA fragments travel toward positive end. The
smaller fragments move faster.
Mixture of DNA
molecules of
different sizes
Longer
molecules
Power
source
Gel
Shorter
molecules
Applications of DNA Technology
Recombinant DNA
in industry

Many species of bacteria have
been engineered to produce
chemical compounds used by
humans.

Scientists have modified the
bacterium E. coli to produce the
expensive indigo dye that is
used to color denim blue jeans.

The production of cheese,
laundry detergents, pulp and
paper production, and sewage
treatment have all been
enhanced by the use of
recombinant DNA techniques
that increase enzyme activity,
stability, and specificity.
Applications of DNA Technology
Recombinant DNA
in medicine

Pharmaceutical companies
already are producing
molecules made by
recombinant DNA to treat
human diseases.

Recombinant bacteria are
used in the production of
human growth hormone and
human insulin
Applications of DNA Technology
Recombinant
DNA in
agriculture

Crops have been
The Most Common Genetically Modified (GM) Crops
developed
that are
better tasting, stay fresh
longer, and are
protected from disease
and insect infestations.
“Golden rice” has been
genetically modified to
contain beta-carotene
Could GM organisms harm human
health or the environment?

Genetic engineering
involves some risks
– Possible ecological
damage from pollen
transfer between GM and
wild crops
– Pollen from a transgenic
variety of corn that
contains a pesticide may
stunt or kill monarch
caterpillars
Transgenic animals :Scientists can study
diseases and the role specific genes play in an
organism by using transgenic animals.

Scientists can study
diseases and the role
specific genes play in
an organism by using
transgenic animals.
Mapping and Sequencing the
Human Genome In February of 2001, the HGP
published its working draft of the 3 billion base pairs of DNA
in most human cells.

The Human
Genome Project
involves:
– genetic and physical
mapping of
chromosomes
– DNA sequencing
– comparison of
human genes
with those of
other species
Applications of the Human
Genome Project

Improved techniques for
prenatal diagnosis of human disorders,
– use of gene therapy,
– development of new methods of crime
detection are areas currently being
researched.
– diagnosis of genetic disorders.
Diagnosis of genetic disorders

The DNA of people with and without a genetic
disorder is compared to find differences that
are associated with the disorder. Once it is
clearly understood where a gene is located
and that a mutation in the gene causes the
disorder, a diagnosis can be made for an
individual, even before birth.
Gene therapy

the insertion of normal
genes into human cells
to correct genetic
disorders.
– Progress is slow,
however
– There are also
ethical questions
related to gene
therapy
DNA fingerprinting

STEPS~use non-coding
DNA
1. Sample DNA cut with
restriction enzymes
2. Fragments separated by
size using gel
electrophoresis
3. Fragments with highly
variable regions are detected
with DNA probe, revealing
DNA bands of various sizes
4. The pattern of bands
produced is the DNA
fingerprint, which is
distinguished statistically
form other individuals