1. If a gray cat is crossed with a black
cat, what is the chance of having a
gray cat?
2. Explain how, looking at a pedigree,
you can determine whether a trait is
dominant or recessive?
TOPIC 27
reminder
Genes are pieces of our DNA
Transcription converts the
information in genes to mRNA
Translation uses the information
Biotechnology is any
technological
A karyotype is an
image of an
individuals
chromosomes.
Remember,
The Human Genome Project was
the international project to
determine the exact sequence of nucleotides and genes of a person
In 1990, scientists decided it would be
good to figure out all of DNA and therefore, all of our genes
This was a huge, unprecedented effort Your DNA is about 2 meters
So what could we do if we knew our DNA?
◦ See what we are made of – what makes us
◦ Detect Diseases
◦ Ways to treat diseases
Drugs
Fix genetic problems ◦ Discover Predisposition
◦ Learn more about Evolution
The ability to TRANSFORM science and
medicine
Scientists are still analyzing the genome
We don’t know all of our genes, and we
When they first sequenced all of our DNA, it
took 13 years and billions of dollars
The process spurred technological advances
Now, we can sequence your DNA for about
$10,000
In about 2-3 years, you will be able to
There have been MANY
technological advances as a
result of the HGP
We now the genomes of several
Genetic Engineering is the
transfer of genes from one organism to another. This new DNA is referred to as recombinant DNA
Stanley Cohen and Herbert Boyer
in 1973 were the first scientists to successfully do genetic
engineering.
Only possible because all
Genetic engineering involves building
recombinant DNA.
Recombinant DNA is DNA that is made
from two different species.
Recombinant DNA is formed when fragments of DNA from two or more
Genetically modified
organisms refer to
organisms that have
been modified via
genetic engineering.
Engineers isolate a specific
gene from one organism and
insert it into another
organism.
Biotechnolo Biotechnolo
Genetically modified plants can
be created that are salt tolerant,
herbicide and pest resistant.
Sheep can be genetically
modified to produce Factor IX in
sheep milk.
GMOs can help reduce starvation
There is no way to predict with
complete certainty what effects
these genetically engineered
plants may have on the
environment.
May create superweed or
superbugs.
Proteins produced by inserted
Other genetic engineering
projects include helping
Genetic engineering
techniques can also be used to produce bigger, more productive
livestock. Injecting growth hormone into
The addition of growth
Human growth hormone
is now being tested for dwarfism, a disorder in which the pituitary gland fails to make enough
A harmless version of a
is called a vaccine. A vaccine is injected into people so that their
immune systems will develop defenses
The body will make defensive proteins called
How do we “do” genetic
engineering and create
genetically modified
A restriction
enzyme cuts DNA
at a specific
nucleotide
sequence
Biotechnology
EcoR1
(
E. coli,
1
ststrain to be discovered)
* cleavage (cut) site
G * A A T T C
C T T A A * G
HinDII (
Haemophilis influenza
, 2
ndstrain)
1. Identify the gene to be
cloned. (Most difficult stage)
2. Cleave gene with a
restriction enzyme.
4. Cleave plasmid with same
restriction enzyme (so that the
sticky ends match).
5. Anneal DNA fragments with
plasmid using DNA ligase.
6. Reintroduce recombinant
How is it possible to insert DNA into an
Polymerase Chain Reations are
used to create copies of specific segments of DNA
Small samples of blood, semen or hair
found at crime scenes often provides an insufficient amount of DNA to carry out forensic tests without PCR
DNA is denatured (destroyed) by
high temperature.
Primers for desired DNA fragment
are attached to each strand.
A new DNA strand is synthesized
behind primers on each template
strand.
Continued rounds of amplification
Gel Electrophoresis
separates DNA
fragments created
by restriction
enzymes based on
size
The smaller the
fragment, the
Gene therapy: A
defective gene is
replaced by a
functional gene
the body can make
the correct enzyme or
protein and cure the
1990 at the NIH a 4 year old girl was
the first to undergo gene therapy.
She was born with Severe Combined
Immune Deficiency (SCIDs) and had
no effective immune system.
White blood cells were removed and
Cloning: creating
and identical
organism using
the DNA of
Twins are naturally occurring
clones.
Cloning to replicate human
beings is considered unethical by
the majority of the scientific
Stem cells are cells that
can differentiate to a
variety of types of cells.
There are 2 types of stem
cells:
Adult stem cells: come
from adults and can
produce many types of
cells
Stem cells can, theoretically, be
stimulated to grow into any
type of cell.
Stem cells could eventually be
used as treatments or cures for
Alzheimer’s, Parkinson’s
Stem cells used to be harvested
from frozen embryos that were
left over from IVF – currently
banned.
Advantage to using own cells is
that the recipient would not have
to take immune-suppressant
drugs.
Most controversial of cloning
Most arguments related to stem cell
research come from people who are
