Download Name: Biology Genetics Problem Set MULTIPLE ALLELES What are

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Biology Genetics Problem Set
MULTIPLE ALLELES
1. What are Multiple alleles?
2. Human blood type is determined by 3 alleles: ____, _____, and ____.
3. Dominant alleles: Both _____ and __ ___ are dominant over i, but neither is dominant over the
other therefore they are _____________ to each other.
4. In humans, the 4 blood types are ____, ____, ____, and ____. These are the phenotype, but notice
that in this case the phenotype is a letter (or 2 letters); not a word.
5. List all the possible genotypes for each of the following blood types:
Type A ____, ____ Type B ____, ____ Type AB _____ Type O _____
List the phenotypes (blood types) for the following genotypes:
IAIB _____
IAi _______
ii ______
A A
B
I I _____
I i _______
IBIB _____
6. Give the possible genotypes and phenotypes (blood types) of offspring of this cross:
IAi
X
IBi
7. Why is it impossible for a parent with type AB blood to have a baby with type O blood?
8. It is possible for 2 parents to have children of all 4 blood types. What must the genotype of the 2
parents be?
9. With the following parents, what would be the probability of having a baby with type O blood?
IAi X IBi
10. It is possible for parents to be of such a genotype, that none of their children are of the same blood
type as either parent. What are the possible genotypes of the two parents? (2 different possible sets
of parents)
11. In a paternity case (who is the possible father of a child), a young woman with type A blood, has an
illegitimate child, blood type O. She feels certain that the child’s father is one of the following 4
men:
a. John (AB).
His father is type A, his mother is type B.
b. Frank (A).
His father is type O, his mother is type AB.
c. Fred (B).
His father is type AB, and so is his mother.
d. Bill (B).
His father is type B, his mother is type A.
A. What is the young woman’s genotype for blood type?
B. Which of the men could be the father?
SEX LINKED
Colorblindness
1. This is a recessive gene carried on the X chromosome (but not on the Y). Usually the normal and
recessive genes are written as: Normal XC; Colorblind X c.
What is the sex and vision of the following:
XC XC ______________________________
XCY________________________________
X c X c______________________________
X cY________________________________
XC X c______________________________
2. A colorblind man married a woman with normal vision (and no history of colorblindness in the
family).
a. What would be the vision of their daughters?
b. What would be the vision of their sons?
One of these daughters marries a man with normal vision.
c. What would be the vision of their daughters?
d. What would be the vision of their sons?
3. Can a female be colorblind? Explain.
Hemophilia
4. What is hemophilia?
5. Why is a male more likely to get this disease than a female?
6. The gene for hemophilia is sex-linked and recessive (h) while its dominant allele (H) produces
normal clotting.
Give the genotype for the following, including the X or Y chromosome. (the possible chromosomes
are XH, Xh, and Y.)
a. Normal male _______
b. Hemophilia male _______
d. Carrier female _______
e. Hemophilia male _______
c. Normal female _______
7. In each of the following, husband and wife are given. Give the possible types of daughters and sons
(by phenotype), including ratios, if any.
a. Carrier normal female x normal male
b. Carrier female x hemophilia male
c. Hemophilia is very rare in females. Why is this so?
CODOMINANCE
Sickle Cell
Using Hs, Ha for the genotypes answer the following questions. Show Punnett squares where appropriate.
8. What are the genotypes for sickle cell?
a. Sickle Cell Disease ________
b. Sickle Cell Trait _______
c. Normal hemoglobin _________
9. A woman who has the sickle cell trait marries a man who does not have sickle cell.
a. What is the probability they will have a child with sickle cell disease? __________
b. What is the probability their child will not have sickle cell at all? ___________
c. What is the probability their child will have the sickle cell trait? __________