Download Unit 5 Applied Genetics Notes

Unit 5 Applied Genetics Notes
Always remember…
• Technology
involved in
genetic
engineering is
called DNA
technology.
• This
technology can
be used to cure
diseases, treat
disorders,
improve crops,
and help make
people’s lives
better.
Isolating specific genes
• Sometimes scientists want to move a gene
from one organism to another. How can
they do this?
• Genetic engineers use restriction enzymes
that come from bacteria to cut DNA
molecules into manageable pieces. These
enzymes can recognize specific
sequences of DNA and cut at that spot.
• When segments are cut, single chain tails
of DNA called sticky tails are created on
each segment to allow them to bind to
complimentary chains of DNA. This allows
new sequences of nucleotides to be
created.
• Once a segment of DNA has been
isolated, it can be transferred to a carrier
chromosome called a cloning vector.
• These chromosomes are normally found in
bacteria in a ring shape and are known as
plasmids.
• The donor gene is inserted into the plasmid and
is then separated from the bacteria. Now you
have a gene clone that has an exact copy of the
gene taken from the original organism. The
new gene can allow an organism to show a new
trait (glowing cats) or produce a new substance
(bacteria that produce human insulin).
• The combination of DNA from two or more
sources is called recombinant DNA.
• A host organism that receives recombinant
DNA is called a transgenic organism.
DNA Fingerprinting
• A DNA fingerprint is a pattern of bands
made up of specific fragments from an
individual’s DNA. Each person’s banding
is unique (just like a regular fingerprint)
and can used to identify that person.
• The method for
preparing a DNA
fingerprint is
called restriction
fragment length
polymorphism or
RFLP analysis.
Fragments of
DNA are
separated in a
process called gel
electrophoresis.
• To make a DNA fingerprint, a sample of
DNA is placed in wells in the gel and then
an electric current is run through the gel.
The DNA fragments become negatively
charged and migrate toward the positively
charged end of the gel.
• Each fragment
of DNA moves
at a different
rate with
smaller
fragments
moving at a
faster rate.
The DNA
fragments are
split into single
chains and
blotted onto
filter paper.
• Segments of
radioactive DNA
called probes bind to
the DNA on the
paper and form
visible bands that
show up when
exposed to
photographic film.
The bands can be
analyzed by a
computer. The
accuracy of the DNA
fingerprints depends
on how unique the
prints are.
Human Genome Project
Human Genome Project
• The two goals of the human genome
project are to determine the nucleotide
sequence of the entire human genome
(about 3 billion nucleotide pairs or 100,000
genes) and to map the location of each
gene on each chromosome.
• This project began in 1990 and was
completed in 2003. In May 2006,
Human Genome Project (HGP)
researchers announced the completion
of the DNA sequence for the last of
the 24 human chromosomes. How does
this differ from the finished human
genome announced by HGP researchers
in 2003?
• The DNA sequences announced
in 2003 were only rough drafts
for each human chromosome.
While this draft already has
advanced medical research,
more detail was needed. The
draft genomic sequences can be
compared broadly to a crosscountry road excavated by a
bulldozer that leaves behind
many gaps across difficult
terrain that will require bridges
and other refinements
Gene Therapy
• Treating a
genetic disorder
by introducing a
gene into a cell
or by correcting
a gene defect in
a cell’s genome
is called gene
therapy.
• Some success in treating
cystic fibrosis has been seen
using gene therapy. A nasal
spray that carries a normal
cystic fibrosis gene can be
sprayed in the nose and
delivered to the lungs where
it is absorbed by the nucleus
of the cells. The treatment
must be repeated
periodically because the
gene is not inserted into the
cell’s chromosomes.
• DNA technology
is used to
produce medical
products that
are often safer
and less
expensive than
those produced
by conventional
means.
• Insulin for diabetics
can be produced by
genetically engineered
bacteria. Human
growth hormone can
be produced and used
to treat dwarfism.
Interferons can be
used to treat viral
infections and some
cancers by preventing
the replication of
viruses.
• Genetically engineered vaccines can
produce a harmless version of a deadly
virus, allowing our bodies to produce
antibodies against a deadly pathogen
that causes us to become ill.
Some crops have been genetically engineered to become
resistant to herbicides used to kill weeds. Other crops could
have new genes introduced to their cells that would cause
them to be sweeter or bigger.
• Clones, animals that are produced from
a body cell rather than sperm & eggs,
could allow us to have herds of critters
with specific traits.
Cc, Copycat,
world’s first
cloned cat.
Cc’s mom
• We could have copies of our pet
Rottweiler, Fluffy, forever! How could that
be helpful to us? How could it be
dangerous?
The End!
•
Idaho Gem
The world's first
cloned mule, was
born on May 4.
He is an identical
genetic copy of
his brother, a
champion racing
mule called Taz,
and the first clone
to be born in the
equine family.
Photo: Gerry
Thomas, Getty
Images