Genetics Problem Sets Worksheet With Answer Key Page 4
ADVERTISEMENT
1
2
3
4
5
6
7
8
9
10
11
12
13
145. In domestic swine there is a dominant allele that produces a white belt around the
body. The recessive allele produces uniform body color. One farmer wants to
produce only belted hogs, and another wants only uniformly colored animals. Which
farmer would have an easier time producing a true-breeding herd? Explain why. Tell
how each farmer would proceed.
6. In cattle, the polled (hornless) condition is caused by a dominant allele, while the
recessive allele causes horns to grow. A polled cow and a polled bull produce a calf
that grows horns as it matures. Show the genotypes of all three. What is the
probability that the pair's next calf will also grow horns.
7. Albinism (as in an "albino") in corn is caused by a recessive allele, and is normally
lethal because the plant cannot manufacture food without chlorophyll, so dies after it
has exhausted the food in the seed. It is possible experimentally to keep albino plants
alive with special feeding techniques in which sugar is supplied to the plant through
the leaves. Show the expected offspring from a cross between an albino plant and a
normal plant that is heterozygous for albinism.
8. In Holstein cattle, spotting of the coat is caused by a recessive allele and solid coat
color by a dominant allele. What types of offspring can occur in a cross between two
spotted animals?
9. A woman has a rare eyelid abnormality called ptosis, which makes it impossible for
her to open her eyes all the way. The condition is caused by a dominant allele. The
woman's father had ptosis but her mother was normal. Her father's mother also had
normal eyelids.
a. What are the genotypes of each of the people mentioned above?
b. What proportion of her children would be expected to have ptosis if she
marries a man with normal eyelids?
10. In humans there is a gene called sickle-cell anemia that produces severe anemia
when homozygous. The name of the disease comes from the fact that many of the
red blood cells take on an abnormal sickle shape. People homozygous for this trait
usually die before adulthood. Heterozygous people appear normal, but a medical
test (holding a sample of the blood under abnormally low oxygen concentration) can
reveal a hidden sickle-cell allele (cells in the blood sample will take on a sickle
shape). A young woman about to be married is concerned about her future children
because her brother died of sickle-cell anemia. A sample of her blood sickles under
low oxygen concentration, but that of her perspective husband remains normal.
What can you say about the man and the women, and about their future children?
Genetics Problems
4
ADVERTISEMENT
0 votes
Related Articles
Related forms
Related Categories
Parent category: Education