Name _______________________________
Date _______
Mrs. Geithner-Marron
Period ______
Problem Set # 3/Review for Genetics Quiz # 3 (Genetic Disorders)
1. Use the word bank to put each genetic disorder into the category that shows how the disorder is inherited.
More than one disorder may be listed in a column.
 colorblindness
 hemophilia
 sickle cell anemia
 Tay-Sachs Disease
 cystic fibrosis
 Huntington’s Disease

down syndrome (trisomy 21)
autosomal recessive

must be

Klinefelter’s Syndrome (XXY)
autosomal dominant

Will have disorder if

Must consider sex & trait
(heterozygous Gg /
(heterozygous Gg/
homozygous
homozygous
dominant GG/
dominant GG/
homozygous
homozygous
o XGXG = ____________,
recessive gg) to
recessive gg)
_________________
trait is (dominant/
recessive)

(Can/ Cannot) be a
carrier b/c trait is
(dominant/
can be a carrier if
(heterozygous Gg /
homozygous
dominant GG/
homozygous
recessive gg)

recessive)
chromosomal
abnormality

Due to changes in
together
_______________ or
There are 5 possible
_________________
genotypes & phenotypes
of chromosomes
o XGXg = ____________,
have disorder b/c

seX-linked
_________________
o XgXg = ____________,
_________________
o XGY = ____________,
_________________
o XgY = ____________,
_________________
Name _______________________________
Mrs. Geithner-Marron
Autosomal Recessive Practice Problems
Date _______
Period ______
2. In dragons, No-fire Disease is caused by an autosomal recessive allele.
Let:


F = normal allele (fire)
f = allele for No-fire Disease
a. A male dragon who is a carrier (heterozygous) for No-fire Disease mates with a female dragon who has
No-fire Disease.

What are the parents’ genotypes?
 Dad = ______
 Mom = ______

Show the cross for these parents using the Punnett Square below.

How many of their children will be (homozygous) normal?
 __________ out of 4

How many of their children will be carriers (heterozygous)?
 __________ out of 4

How many of their children will have No-fire Disease?
 __________ out of 4
mom
dad
Name _______________________________
Mrs. Geithner-Marron
Date _______
Period ______
3. Tay-Sachs disease is caused by an autosomal recessive allele.
Let:


T = normal allele
t = allele for Tay-Sachs Disease
a. A man who is a carrier (heterozygous) for Tay-Sachs Disease mates with a female who is also a carrier for
Tay-Sachs Disease.

What are the parents’ genotypes?
 Dad = ______
 Mom = ______

Show the cross for these parents using the Punnett Square below.

How many of their children will be (homozygous) normal?
 __________ out of 4

How many of their children will be carriers (heterozygous)?
 __________ out of 4

How many of their children will have Tay-Sachs Disease?
 __________ out of 4
mom
dad
Name _______________________________
Mrs. Geithner-Marron
Date _______
Period ______
4. Sickle Cell Anemia is an autosomal recessive disorder. Suppose two people who were heterozygous for
Sickle Cell Anemia married and had a child.
 Let: S = normal allele & s = allele for Sickle Cell Anemia.

Show the cross using a Punnett Square

What is the probability that the child will have Sickle Cell?
5. The gene for Cystic Fibrosis is an autosomal recessive allele.
 Let: C = normal allele & c = allele for Cystic Fibrosis.

Show, using one or more Punnett Squares, how 2 normal parents can have a child with CF.
Name _______________________________
Mrs. Geithner-Marron
Autosomal Dominant Practice Problems
Date _______
Period ______
6. In Snorks, Bent Snorkel Disease is caused by an autosomal dominant allele.
Let:


B = allele for Bent Snorkel Disease
b = normal allele
a. Steven Snork, who is homozygous for Bent Snorkel Disease, marries Sally Snork who is normal.

What are the parents’ genotypes?
 Dad (Steven)= ______
 Mom (Sally)= ______

Show the cross for these parents using the Punnett Square below.

How many of their children will be homozygous for Bent Snorkel Disease?
 __________ out of 4

How many of their children will be heterozygous for Bent Snorkel Disease?
 __________ out of 4

How many of their children will be normal?
mom
 __________ out of 4
dad
Name _______________________________
Mrs. Geithner-Marron
Date _______
Period ______
7. Huntington’s disease is caused by an autosomal dominant allele.

Let: H = allele for Huntington’s Disease & h = normal allele
a. Can a person be a carrier? Explain your reasoning.
b. A woman who is heterozygous for Huntington’s Disease marries a normal man.

What are the parents’ genotypes?
 Dad = ______
 Mom = ______

Show the cross for these parents using the Punnett Square below.

How many of their children will be homozygous for Huntington’s Disease?
 __________ out of 4

How many of their children will be heterozygous for Huntington’s Disease?
 __________ out of 4

How many of their children will be normal?
 __________ out of 4
mom
dad
Name _______________________________
Mrs. Geithner-Marron
Date _______
Period ______
seX-linked Practice Problems
8. In Snorks, Deviated Snorkel disease is recessive and seX-linked.
Let:



XD = normal allele
Xd = allele for Deviated Snorkel Disease
Y = no allele
a. Sam Snork has Deviated Snorkel Disease. He marries Sue Snork, who is a carrier.
 What are the parents’ genotypes?

Dad (Sam)= ______

Mom (Sue) = ______
 Show the cross for these parents using the Punnett Square below.
 What is the chance that their child will be male and normal?

__________ out of 4
 What is the chance that their child will be male & have Deviated Snorkel Disease?

__________ out of 4
 What is the chance that their child will be female and (homozygous) normal?

__________ out of 4
 What is the probability that their child will be female and a (heterozygous) carrier?

__________ out of 4
mom
 What is the probability that their child will be female and
have Deviated Snorkel Disease?

__________ out of 4
dad
Name _______________________________
Mrs. Geithner-Marron
Date _______
Period ______
9. In Humans, hemophilia is a recessive and seX-linked disease.
Let:



XH = normal allele
Xh = allele for Hemophilia
Y = no allele
a. A man who is normal marries a woman who is a carrier.
 What are the parents’ genotypes?

Dad = ______

Mom = ______
 Show the cross for these parents using the Punnett Square below.
 What is the chance that their child will be male and normal?

__________ out of 4
 What is the chance that their child will be male & have Hemophilia?

__________ out of 4
 What is the chance that their child will be female and (homozygous) normal?

__________ out of 4
 What is the probability that their child will be female and a (heterozygous) carrier?

__________ out of 4
mom
 What is the probability that their child will be female and
have Hemophilia?

__________ out of 4
dad