Download File - Mr. Lambdin`s Biology

DNA Mutations and Genetic
Diseases
Ch 13, 14, 15
What is a Mutation?
• Changes in the
normal sequence of
DNA
• Many different types
and sizes
• One letter mistakes
to whole chromosome
mistakes
MUTATIONS can be:
HARMFUL
defective proteins
-Mutations that produce ______________
are
usually harmful.
-Harmful mutations are associated with many
genetic
disorders
________________
and can cause cancer
MUTATIONS can be:
BENEFICIAL Mutations are also a source
____________genetic variation
of ______________
in the
population
Mutations can help an
organism
_________________
survive
and reproduce
Provide a way for
species to change
over time (evolution)
REMEMBER!
MUTATIONS
_______________
are changes
in the genetic material.
Mutations can happen:
mistakes in copying DNA
• when cells make_________
• when cells are exposed to environmental
carcinogens
___________ like
radiation
__________- X-rays, tanning booths
__________ - cigarette smoke, pollutants
chemicals
viruses
__________
- HPV
Gene Mutations
• A mutation is a change or alteration, either in
form or qualities
• Mutations involving 1 or more genes
• Point Mutations = substitute one letter in for
another (A,G,T,C), usually not a problem
• Frameshift Mutations = insert or delete
letters, throws off how the entire sequence
is read = problem
Chromosome Mutations
• Changes in the number and structure of
chromosomes
• Chromosome Duplication: extra piece of
chromosome or an entire extra
chromosome
• Chromosome Deletion: a piece of
chromosome is lost or an entire
chromosome is missing
Karyotype-picture of a persons
chromosomes
Results of DNA Mutation Notes
Failure to Make the Right Proteins
Down Syndrome
• Trisomy 21 = 3 number 21
chromosomes
• Symptoms = distinct facial
features, low
communication skills,
hearing and seeing
problems, lower IQ
• Occurs mostly when women
have children after 40
Phenylketonuria (PKU)
CAUSE:
ENZYME
Mutation in gene for an ___________
breaks down
amino acid
that __________
an ___________
called
phenylalanine
X
X
MENTAL RETARDATION
Build up causes ________________________
http://biology.clc.uc.edu/courses/bio104/protein.htm
Phenylketonuria (PKU)
ALL babies are ________
tested
____
for PKU before they
leave the hospital.
http://labspace.open.ac.uk/file.php/2588/SK195_6_002i.jpg
Treatment:
LOW in phenylalanine
Need a diet _____________________
to extend life and
PREVENT
______________
mental retardation
amino acid
If phenylalanine is an _____________,
what type of foods should PKU patients avoid?
PROTEINS !
__________________
THINK ABOUT IT
What does a can of
Diet Coke have to do
with human genetics?
LOOK AT THE WARNING LABEL !
NUTRASWEET
______________ is made with phenylalanine
Hemophilia
• Blood doesn’t clot
correctly
• Risk of bleeding to death
• A X chromosome deletion
• 1 in 400 babies affected
yearly
• Treatments add clotting
factors to blood so that
it will clot correctly
Albinism
• Lack of melanin pigment
• Cause: gene mutation on #11,
#15, or #9
• Symptoms: little or not
pigment in the skin, hair, and
eyes; bad vision, sensitive skin
• 1 in 17,000 people
• Special glasses and protective
clothing must be worn when
outside
Proteus
Syndrome
• Deletion on
chromosome #11
• Symptoms: atypical
bone growth,
tumors on and
beneath skin
• Very rare
• The elephant man?
Achondroplasia
• Gene affected on
chromosome #4
• Symptoms = short
arms and legs, normal
sized head and spine,
normal IQ
• Possible for 2 dwarfs
to have a normal sized
child
• 1 in 15,000 people
have it
Sickle Cell Anemia
• Gene on chromosome
#11 is affected
• 1 in 635 babies,
more common in
African Americans
• Sickle shaped blood
cells result in painful
arms and legs,
breathing problems,
dehydration, swelling
Huntington’s Disease
• Duplication on chromosome #8
• Uncontrollable muscle spasms,
deterioration of the brain,
death
• Symptoms don’t show up until
30 –50 years old, so you pass it
on to your kids without even
knowing (50% chance)
Turner
Syndrome
• Female who is missing
an X chromosome
• Symptoms: short,
webbed neck, infertile,
bone deformations
• Hormone replacement
therapy helps relieve
symptoms
Klinefelter’s Syndrome
• Men that are XXY
• 1 in 700 men have it
• Symptoms: Normal males
(some develop feminine
traits) they are just
infertile
• Most men don’t know
that they have it until
they try to have children
Cleft Lip and
Palate
• A large gap in the roof
of the mouth and lip
• Didn’t form correctly
before birth
• Side effect of other
genetic diseases and of
fetal alcohol syndrome
(drinking while pregnant)
• Surgery can return to
normal, but expensive
Cri du Chat
Syndrome
• Missing piece of
chromosome #5
• Symptoms: slow
growth rate, high
pitched scream (cat
like), low IQ,
webbed fingers and
toes
• Very rare
Progeria or(Hutchinson Gilford)
• Caused by a “fresh” mutation or
has occurred only by chance in
the child and does not occur in
either of the parents.
• Only 10-12 people worldwide
have it at one time
• Age 10 times faster
• Die of heart failure at 10-15
Manipulating
DNA
Chapter 14-3
Manipulating DNA
• Scientists can cut and paste DNA to
get specific sequences that they want
• Very similar to cutting and splicing
video tapes
Tools of DNA Manipulation
• Cutting DNA =
Restriction
Enzymes
– Specific enzymes
cut DNA at
specific sequences
– (ex) ecoR 1 cuts
the DNA at every
CTTAAG sequence
Tools of DNA
Manipulation
• Separating DNA = gel
electrophoresis
– The cut up DNA is put on
the jelly and a electrical
current is passed
through it
– The DNA gets separated
by size
– The largest pieces don’t
travel as far as the
smaller pieces
Tools of DNA Manipulation
• Making Copies of the DNA
= PCR
– A Polymerase Chain
Reaction machine makes
copies of the sequences
that you want
• Reading the DNA = dyes
and special microscopes
- dyes make it possible to tell
the difference between A,
T, G, and C
What can we do with
these tools?
1.
Forensics: see if DNA
from the crime scene
matches a criminal’s DNA
2. Putting specific genes into
plant and animal cells
3. Putting human genes into
bacteria to make multiple
copies for synthetic use
4. Genetically modified foods
Human Genome
Project
Our Findings
Goals of HGP
• Sequence Entire Human
Genome
• Identify Genes
• Chart Variation
• Sequence other organisms
Successes
• Completed Early (19902003)
• Discovered
– Only 20,000 Human Genes
– vs. 100,000 Human
genes(previous guess)
• Mapped Genomes
–
–
–
–
Chimpanzee
Mouse
Rat
Fruit Fly
Other Successes
• Unraveled Cancer genetics
– Individualize treatment
• Changed Ideas of DNA
– Epigenetics
• SNP’s (Single Nucleotide
Polymorphisms)
– Different by 10 million letters
– Only .1 % of total genes
What’s Next?
• Understand functions of genes
• Catalogue Human Variation
• How it all works together?
In the course of human progress, it has been
far easier to understand the things we make,
rather than what makes us
Genetic Engineering
Chapter 14-3
Genetic Engineering
• Humans changing
the sequence of
DNA
• Get traits that we
want
• Selective breeding,
cloning, DNA
manipulation and
transformation
Selective
Breeding
• Humans controlling who
gets to breed so that we
can control the traits in
the next generation
• All domestic animals: dog
breeds, milk and beef
producing cows, etc…
Hybridization
• Cross two dissimilar
organisms to get offspring
with the best traits from
both
• Only breed the cows that
produce the most milk
• Cross a corn plant that
produces a lot of corn to
one that resistant to
insects
• Horse X Donkey = Sterile
Mule
• Zorse (zebra and horse)
• Cama ( Camel and Llama)
Inbreeding
• Continued breeding of individuals with the
desired characteristics
• Maintains the traits that you want
• Over inbreeding = joint deformities and blindness
Modern Biotechnology
some examples
•
•
•
•
•
•
Recombinant DNA
Stem cell therapy
Cloning
Designer drugs
Genomics
Gene Therapy
What are the
potential benefits?
What are the
potential dangers?
What are the
ethical issues?
Recombinant DNA
• Taking the DNA of one organism and
attaching it to the DNA of another.
• Uses Plasmids
– Circular pieces of bacterial DNA
– Must contain a replication start signal (ori)
– Must contain a restriction enzyme cutting
site
• http://webapps.css.udel.edu/biotech/rDNA.html
Genetically Modified Bacteria
Cloning
• Creating Genetically identical
individuals
• 1997 the sheep Dolly was
cloned and she produced a
viable offspring so it was a
success
• An egg is removed and a cell
from the adult that you want
to clone is fused with it. The
egg cell is than placed into a
foster mother where it
develops normally
Cloning in Agriculture
Other Cloned Animals
• Five cloned pitbull
puppies are seen with
their 'mom' at the Seoul
National University
Hospital for Animals in
South Korea.
Prometea and Pegaso
(Cloned horse and
offspring from cloned
horse.)
Transgenic Organisms
• organisms that have
genes from other
organisms inserted into
their DNA
• Bacteria = human insulin
producers
• Animals = lab rats with
human immune systems,
bovine growth hormone
• Plants = plants that
have genes that make
them resistant to
insects, herbicides, and
drought
GMO’s
• Genetically Modified
Organisms
• Almost all of the
fruits in vegetables
sold in the USA have
been genetically
modified
• (92% soy beans, 80%
corn etc..)
• Should they be
labeled????
GMO Benefits
• Decreased Pesticide
Usage
– Bt toxin gene
• Decreased Spoilage
• Prevent Disease
– Golden rice (vitamin A)
• Source of Human
Medicine
– Human proteins from milk
– Insulin
– Blood clotting factors
GMO Cons
• Cause extinction of
beneficial insects
– Bt toxin
• No safety testing of GMO
food
– Allergies
– Long term
• Non-scientific purposes
– Cloning Humans/Pets
– Designer babies
– Glo-Fish