BIO 313 Final Review A
Supplemental Instruction
Iowa State University
Leader:
Course:
Instructor:
Date:
Laura
Bio 313
Dr. Rodermel
12/9/15
Vocab Review:
1060 Hixson-Lied Student Success Center  515-294-6624  sistaff@iastate.edu  http://www.si.iastate.edu
Practice Problems:
1. A researcher notices something strange in this drosophila. He notices that 1/2 of the females
have white eyes compared to red and that the males follow the same phenotypic pattern. It is
unknown whether this trait is located on the X or Y chromosome. Complete a reciprocal
cross and identify whether the gene is X or Y linked.
2. The following phenotypes of guinea pigs are known: Black (B) is dominant to white (b) and
short hair (L) is dominant to long hair (l). If a Black-long hair were crossed with a white
short hair, what would be the phenotypic and genotypic ratios of the F1 generation? What
would be the phenotypic ratio of the F2 generation?
3. Guinea pigs can also have a condition called bowlegged, where their legs curve noticeably
outward. Bowleggedness is a dominant lethal allele if an individual inherits two copies of it
(BB). Show the cross between a long-haired, bowlegged guinea pig and a heterozygous
short-haired pig that is also bowlegged. How many of their offspring would you expect to be
normal with curly hair?
4. Complete the following questions about sex-linked traits:
a. A woman with hemophilia marries a man who does not have hemophilia. What are
the possible phenotypes of their children?
b. A woman without hemophilia marries a man with hemophilia. They have a daughter
with hemophilia. What is the genotype of the mother and father?
c. A colorblind man marries a female who is a carrier for colorblindness. What is the
probability that they will have a child who is colorblind?
d. A colorblind male marries a female who is not colorblind (homozygous). What are
the possible phenotypes of their children?
5. Explain Polydactyly in terms of its penetrance and expressivity:
6. 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.
a.
What would happen if they crossed a yellow jellyfish with a goober?
b. What would happen if they crossed a blue jellyfish with a yellow jellyfish?
i.
If 100 jellyfish were produced from this cross, how many would you expect
for each?
7. In a certain cactus, prickly spines can be two pronged or one pronged. If a true breeding onepronged cactus is crossed with a true breeding two-pronged cactus, the F1 generation has a
mixture of spines, some are two-pronged, some are one-pronged. Is this an example of
codominance or incomplete dominance?
a. Show the F2 generation (a cross between the two F1's). What are the phenotypes of
the offspring and in what proportion?
8. Two unlinked loci effect mouse hair color. AA or Aa mice are agouti (brown). Mice with
genotype aa are albino because all pigment production is blocked, regardless of the
phenotype at the second locus. At the second locus, the B allele (agouti coat) is dominant to
the b allele (black coat). What would be the result of a cross between two agouti mice of the
genotype AaBb?
9. Margaret has just learned that she has adult polycystic kidney disease. Her mother also has
the disease, as did her maternal grandfather and his younger brother (both of whom are now
dead). As far as Margaret knows, no one else in her extended family has the disease,
although she had a sister, Allison, who died in a car accident when she was 16 and might
have showed symptoms if she had lived long enough. Margaret is 42 years old and has three
children with her husband, Art. Anna is 20, Lydia is 18, and Tom is 15. Her husband’s name
is Art.
a. Could this disease be autosomal recessive? If so, is this mode of inheritance likely?
Explain.
b. Could this disease be autosomal dominant? If so, what is the chance that Lydia will
get the disease when she reaches middle-age?
c. Could this disease be X-linked recessive? Explain, using specific individuals in the
pedigree to support your answer
d. Could this disease be X-linked dominant? Explain, using specific individuals in the
pedigree to support your answer.