6. What would be the ratio of curled ear to normal ear
kittens if two kittens from #5 are mated? **
Practice Genetics Problems
Name:
For each problem, drag and drop the letters in
the Punnett Square, and answer the question.
1. Albinism is a recessive trait.
Mrs. Jones is a carrier for the albino trait. Her
husband is normal. What is the probability that their
first child will be a carrier? **
AA
A
a
Aa
2. Mr. Smith is albino. His wife is normal. What is the
probability that their second child will be albino? **
A
a
Aa
aa
3. Rough coat is dominant to smooth coat in guinea
pigs. A purebred rough guinea pig is mated with a
smooth guinea pig. What is the probability of smooth
piglets? **
R
r
E
EE
e
Ee
ee
7. Black fur is dominant to brown fur in rabbits. If a
farmer has a black rabbit, what can he do to figure
out if it is purebred or hybrid? Design an experiment
that would help him figure this out. **
8. Achondroplastic dwarfism is a dominant trait in
humans. Two dominant alleles is a lethal genotype.
What is the probability of two dwarf people having a
normal child? **
D
d
DD
Dd
dd
9. A normal woman and a dwarf man plan to have
children. What is the probability of them having
normal children? **
D
d
Dd
dd
Rr
4. Two hybrid rough guinea pigs are mated. What are
the probabilities and phenotypes of all possible
offspring? **
R
r
RR
Rr
rr
5. Curled-ear is a dominant trait in cats. What is the
probability of getting curled-ear kittens by mating a
purebred curled-ear male to a normal-eared female?
**
E
Ee
e
10. Huntington's disease is caused by a dominant allele.
Homozygous dominant is a lethal combination.
People who inherit one dominant allele from a
parent will develop the disease in middle age. It is
fatal and there is no cure. Unfortunately, people
usually have kids before they show symptoms.
What are the chances that a person with
Huntington's will pass the gene on to his or her
kids? (assume the partner is normal) **
H
h
Hh
hh
11. Tay-Sachs disease is caused by a recessive allele.
What are the chances that a couple with one TaySachs child will have another Tay-Sach child if
they conceive again? **
T
t
TT
Tt
14. A purebred tall, hybrid axial pea plant is crossed
with a hybrid tall, purebred axial pea plant. What is
the probability of getting tall and axial offspring?
**
tt
12. Wrinkled seeds is a recessive trait. What is the ratio
of wrinkled and round offspring if a hybrid round
and a wrinkled pea plant are crossed? **
R
Rr
r
rr
TA
Ta
TTAA
15. Two short, terminal-flowered pea plants are crosspollinated. What is the probability of getting tall
offspring with axial flowers? **
13. Tall is dominant to short. Axial flowers are
dominant to terminal flowers.
What is the probability of getting a short, terminal
pea plant by crossing a purebred tall and purebred
axial pea plant with a purebred short and terminal
pea plant? **
ttaa
TA
ta
TtAa
TTAa
ta