Transcript Genetics and People Modern Genetic Research Mutations • Mutation: change in DNA – Mutations in body cells effect present organism, but CAN NOT BE.

Genetics and People
Modern Genetic Research
Mutations
• Mutation: change in DNA
– Mutations in body cells effect present
organism, but CAN NOT BE PASSED ON to
offspring
– Mutations in sex cells CAN be passed on to
the offspring
• WHY?: Nonsex cells are not apart of the
fertilization process—only sex cells are
Mutations
• Chromosomal Alterations:
– Nondisjunction
• Example: Down’s Syndrome
– Polyploidy
• Example: 3n or 4n
set of chromosomes
• Most mutations are harmful and recessive
Genes and the environment
• The environment interacts with
genes in the development and
expression of inherited traits
• Here is an example…
Nature vs. Nurture
• In many cases it is not only the genes
that we have that determine what we
look like
• Scenario: If identical twins (same DNA)
were separated at birth and lived in 2
different environments and then
brought together 25 years later would
they look the same? Why or why not?
Bell Ringer: March 10
• If you have a mutation in your toe cells
due to toxic waste. Will your offspring
have a mutation as well?
Nature vs. Nurture
• Answer: The identical twins would have
similar features (eye color, size of nose,
etc.) but may look very different. What
they did throughout their lives effects
what they look like
– For example: sun exposure,
diet, hygiene, injuries, etc.
Gene Expression
• Snowshoe Rabbit:
– Color of rabbit in the summertime: brown
– Color of rabbit in the winter: white
– The temperature effects what color fur (or
what proteins) are expressed
Gene Expression
• Green color in plants:
– Most plants have chlorophyll and the ability to
be green
– The sun activates the protein in chlorophyll to
turn plants green in color
Chlorophyll
No
Chlorophyll
Changing Chromosome Structure
• Translocation: transfer of one section of a
chromosome
• Addition: a portion of one chromosome is
attached to another chromosome
• Deletion: a portion of a chromosome is taken
away from a chromosome
• Inversion: a portion of a chromosome breaks off
and then becomes reattached to the same
chromosome in an inverted (upside down)
fashion
Genetic Research
• Knowledge of genetics is making possible new
fields of health care
• Mapping of genetic instructions in cells makes it
possible to detect, and perhaps correct,
defective genes that may lead to poor health.
• Substances from genetically
engineered organisms may reduce
the cost and side effects of
replacing missing body chemicals.
Genetic Research
• Cloning: producing a
group of genetically identical
offspring from the cells of an
organism
• This technique shows great promise in
agriculture
– Plants with desirable qualities can be rapidly
produced from the cells of a single plant
Recombinant DNA
• Recombinant DNA:
– Also called genetic
engineering
– Creates new varieties
of plants and animals
by manipulating the
genetic instructions of
these organisms to
produce new
characteristics
Genetic Research
• Genetic Engineering: (recombinant DNA)
– transfer of genetic information from one
organism to another
– includes the transfer of entire genes and gene
splicing
– Genetic engineering can
– correct genetic defects &
– produce agriculturally more
efficient plants and animals
Recombinant DNA
• A cell can synthesize a new chemical
coded for by its new genes
• Examples:
– Interferon: helps fight infections
– Insulin: combat diabetes
– Growth hormone: help stimulate growth
Recombinant DNA
X
(X)
How Recombinant DNA Works
• Restriction Enzymes: enzymes used to cut
segments of DNA in one organism so they can
be transferred into another organism
– Characteristics produced by the segments of DNA
may be expressed when these segments are inserted
into new organisms such as bacteria.
– Inserting, deleting, or altering DNA segments can
alter genes. An altered gene may be passed on to
every cell that develops from it.
Difficulties with Genetic
Engineering
•
•
•
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The moved gene may not be expressed
It is difficult to isolate the gene
The trait may be recessive
There may be unintended adverse
qualities
Human Genome Project
• Human Genome Project: has allowed
humans to know the basic framework of
their genetic code
– Knowledge of genetics is making possible
new fields of health care
– Genetic mapping is making it possible to
detect and possibly correct, defective genes
that may lead to poor health.
More on Genetic Research
• A down side to this is that health insurance
agencies and other organizations may use
this genetic information against
individuals.
• Substances from genetically engineered
organisms may reduce the cost and side
effects of replacing body chemicals.
Human insulin produced in bacteria is
already an example of this.
Bell Ringer: March14
• What is one genetic disorder and how is it
detected?
Future of Genetic Engineering?
Genetic Disorder
Name of
Disorder
Technique used to Diagnose
Characteristic of
Disorder
Sickle Cell
Anemia
Microscopic examination of blood Low oxygen supply of
cells
Down’s
Syndrome
Karyotype
Mental Retardation
PKU
Urine analysis
Mental retardation
Amniocentesis
• One final way to check for genetic
diseases is through amniocentesis
– Checks the proteins of the developing fetus
while in the womb