Download Beyond Mendel Practice Problems

Beyond Mendel Inheritance Practice Problems
Name: __________________
Part I: Codominance
1. A man with AB blood marries a woman with O blood. Show the cross
and list the phenotypic ratio.
2. A woman with A blood (whose parents were both AB blood) marries a man with B blood (his mother
was AB and the father was O blood). Show the cross and the phenotypic ratios.
3. A woman with A blood gives birth to a child with AB blood and her husband has B blood.
Could the child possibly be his?
4. A woman with O blood gives birth to a child with B blood and her husband has A blood.
Could the child possibly be his?
Part II: Incomplete Dominance
SpongeBob loves growing flowers for his pal Sandy! Her favorite flowers, Poofkins, are found in red, blue, and
purple. Use the information provided and your knowledge of incomplete dominance to complete each section
below.
5.
What would happen if SpongeBob crossed a Poofkin with red flowers with a Poofkin with blue flowers.
a. How many of the plants would have red flowers? _____%
b. How many of the plants would have purple flowers? _____ %
c. How many of the plants would have blue flowers? _____ %
6. What would happen if SpongeBob crossed two Poofkins with purple flowers?
a. How many of the plants would have red flowers? _____%
b. How many of the plants would have purple flowers? _____ %
c. How many of the plants would have blue flowers? _____
SpongeBob and his pal Patrick love to go jellyfishing at Jellyfish Fields! The fields are home to a special type of
green jellyfish known as Goobers and only really great jellyfishermen are lucky enough to catch some on every
trip. Many of the jellyfish are yellow (YY) or blue (BB), but some end up green as a result of incomplete
dominance. Use this information to help you complete each section below.
7. What would happen if SpongeBob and Patrick crossed two “goobers” or green jellyfish?
a. What percentage of the offspring would be yellow? _____%
b. What percentage would be blue? _____ %
c. What percentage would be “goobers” (green)? _____ %
8. What would happen if they crossed a yellow jellyfish with a goober? Complete the Punnett square to help you
determine the probability for each color of jellyfish.
a. What percentage of the offspring would be yellow? _____%
b. What percentage would be blue? _____ %
c. What percentage would be “goobers” (green)? _____ %
Part III: Sex-linked
1. Complete the basic punnett square of sex determination.
a. Which sex chromosomes do males have? ______________
b. Which sex chromosomes do females have? _____________
c. Out of 4 children, how many are expected to be male? _____
d. Out of 4 children, how many are expected to be female? _____
2.
Hemophilia is an X-linked recessive trait. The clotting factor in the blood of hemophiliacs does not
function properly and causes uncontrollable internal or external bleeding.
a. A man has hemophilia. What is his genotype? ________________
b. What is the chance he will pass the hemophilia allele on to his children? _______________
c. From which parent(s) did he get the hemophilia allele? _____________________________
3. Colorblindness is an X-linked recessive trait. The cones in colorblind individuals are unable to process
certain wavelengths of light resulting in an inability to distinguish between certain colors to no color
perception at all.
a. A woman has colorblindness. What is her genotype? ________________
b. What is the chance she will pass the colorblindness allele on to her children? _______________
c. From which parent(s) did she get the colorblindness allele? _____________________________
4. Hemophilia is a recessive sex-linked trait. Complete the punnett
square considering the following parents: XHXh x XHY
What are the chances for these two parents to have …?
a. A boy with hemophilia?
b. A girl with hemophilia?
______________%
______________%
5. Red-green color blindness is a recessive sex-linked trait. A colorblind male marries a normal female.
Complete the punnett square, noting that one of their daughters is
colorblind.
a. What are the genotypes of both parents and the daughter?
Dad = __________
Mom = _________
Daughter = ___________
c. Can a colorblind father have daughters who are not colorblind?
d. Explain:
6.
Normal vision (C) is dominant over color blind (c). This gene is located on the X chromosome.
A normal vision man and woman produce three boys, one of which is color blind and the other
two with normal vision. What are the genotypes of the parents?
Father ____________________
Mother ___________________
7. In fruit flies (Drosophila) the gene for red or white eyes is located
on the sex chromosome. Red (XRXR or XRXr) is dominant to white
(XrXr). Complete the punnett square and state the possible
genotypes of both parents when the following F1 offspring were
observed:
10 red-eyed males
Parental Genotypes:
10 red-eyed females
Male ____________________
10 white-eyed males
Female __________________
10 white-eyed females
8. Luis, a colorblind person got married, divorced, and remarried. He and his first wife, Maria, has a
colorblind son, a colorblind daughter, a normal son and a normal daughter. However, he and his current
wife, Carla, have four boys and two girls, none of whom is colorblind.
a. Write the genotype of each wife.
b. State (yes or no) if she is colorblind.
Linda (1st Wife) __________ Mary (2nd Wife) __________
Linda (1st Wife) __________ Mary (2nd Wife) __________
9. In cats, one gene for coat colors is X-linked. Male cats are either black or orange, depending on which
allele they carry. Females are black, orange, or tortoise-shell (patches of black and orange), with the
tortoise-shell phenotype resulting from the heterozygous genotype. The cats mate and have kittens. Of
the female kittens, ½ are tortoise-shell and ½ are orange. Of the male kittens, ½ are orange and ½ are
black.
a. What are the genotypes of the parent cats? Male _______________ Female ________________
b. What are the phenotypes of the parent cats? Male _______________ Female ________________
10. Complete the following concluding questions:
a. Why are men never heterozygous for an X-linked trait?
b. Why must men always inherit a sex or X-linked trait from their mothers?
c. Can a color-blind father pass this allele on to his sons? Explain.
d. Can a normal male ever have a daughter that is color-blind? Explain.