Download Alzheimer`s Disease

Diego, Jackie, and Pete
1/27/10
Period 2
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Alzheimer’s Disease is a progressive and
fatal brain disease.
Over 5 million people have it.
Early symptoms include memory loss,
trouble concentrating, and inability to
remember facts, events and later family and
friends.
Alzheimer’s disease is the 4th leading cause
of death in adults.
AD is twice as common in women than it is
in men.
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Alzheimer’s affects the 1st, 14th, 19th, and 21st
chromosomes.
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Alzheimer’s does have a genetic link, and it is a
Dominant disorder.
FAD (Familial Alzheimer's Disease) occurs in a
very small percentage of people with
Alzheimer's disease (5-7%)
Sporadic Alzheimer's Disease is much more
common (around 90-95 %) and people with this
type do not necessarily have a family history of
the disease.
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An allele is an alternative form of a gene (one
member of a pair) that is located at a specific
position on a specific chromosome.
Humans have 2 alleles per gene.
The two alleles come from both parents.
Recessive alleles are represented by rr. Dominant
alleles are represented by RR or Rr.
Phenotypes are specified by single gene
substitutions are called Dominants and those that
require homozygous combinations for expression
are called recessives.
In the First Punnett square, the offspring has 75% chance of having
Alzheimer's. In the second one, the probability is 100% and in the 3rd one its
50%. The last one has 100% also.
1
Father
G
G
Mother
g
3
GG
Gg
h
Father
g
Gg
gg
h
Father
W
W
Father
w
Ww
Ww
Xr
w
Ww
Mother
Ww
Y
H
Hh
Hh
XR
XRXr
XrY
h
hh
hh
XR
XRXr
XRY
Mother
2
4
Mother
G
g
G
g
GG
Gg
Gg
gg
Ratio:
This Punnett square has 1GG :
2Gg : 1gg.
Percentage:
25% GG, 50% Gg, and 25% gg
.
G
g
G
GG
Gg
g
Gg
gg
The letters are the Genotypes, or
what is in the genes. The
Phenotypes are what you see. GG
would mean that the offspring does
have Alzheimer’s. Gg would also
mean that, but gg would not since
they are both recessive.
The four squares in the
middle are the chances
for the offspring. GG is
a Homozygous
Dominant, Gg is a
Heterozygous
Dominate, and gg is a
Heterozygous
Recessive.
G
g
G
GG
Gg
g
Gg
gg
Genotypes:
Ratios: 1GG : 2Gg : 1gg.
Percentages: 25% GG, 50% Gg,
25% gg.
Phenotypes:
Ratios: 3 with
Alzheimer's disease, 1
without it. 3:1
Percentages: 75% will
have it, 25% will not.
G
G
GG
GG
Gg
Gg
G
g
Fill in the offspring possibilities of them
having Alzheimer’s Disease. After that
is completed fill out the following:
Genotype:
Ratio:
2GG : 2Gg
Percentage:
Phenotype:
Ratio:
50% GG, 50% Gg
4 Alzheimer’s : 0 No Alzheimer's
Percentage:
100% Chance of
Getting Alzheimer’s Disease.
Autosomal Dominant
Red Square
= affected
male, Blue
Square =
not
affected
male. Red
Circle =
affected
female,
Blue circle
= not
affected
female.
1. Are dominant conditions expressed in
individuals who have just one copy of the
Yes
mutant allele?
2. Do affected individual's have one normal copy
of the gene and one mutant copy of the gene? Yes
3. Will the offspring have a 75% chance of
inheriting the mutated allele?
No, a
50%
chance.