Possible Test Questions for Thursday
Be thorough in your responses and write in complete sentences.
1. Explain how someone can have one recessive allele and have the
recessive phenotype. Please use a specific example in your answer.
2. This question has two parts.
You have a tall, green pea plant with an unknown genotype. You do a
test cross with a dwarf, yellow pea plant to figure out the genotype of the
tall plant. Dwarfism and yellow peas are both recessive traits. All of the
F1 plants are tall with green peas. What is the genotype of the unknown
parent?
What are the expected results for a cross between two of these offspring?
Be sure to include plant descriptions of each of the expected phenotypes.
3. Assume that the production of a cicada attracting hormone (a) is a
recessive trait to not making the pheromone (A). People that make the
pheromone often have cicadas flying directly at their face and are known
as cicadophiles. Use the key below to answer the questions.
If Mr. and Mrs. Buggle are a both cicadophiles, what are their
genotypes?
Mr. Buggle _____________ Mrs. Buggle_______________
What must be the genotype of all of their children Billy, Bobby, Barbara,
Biff, Bonnie, Baxter, and Beth? (shown in birth order)
Draw a pedigree for the Buggle family below. Use shading to indicate
genotype. Also, write the names and genotypes below each of the circles
or squares.
Now let’s look at the Citronella family. Joey Citronella always has
cicadas fly into his face but his parents and sisters Jane and Joanne never
do. Joey gets married and he and his wife have 3 kids (Jim, Jason and
Joey Jr.) and just Joey Jr. has cicadas flying around him but the other two
do not. Joey’s wife Jen never had a cicada fly into her mouth.
Jane has two children, Kathy and Kendra, with her husband,
Ken. Neither Ken nor the kids have cicadas flying around them.
Joanne was a wild child and had a baby girl with someone she
only met once. Her child, Zoe, always attracts cicadas.
Draw a pedigree for the Citronella family below. Use shading to indicate
genotype when full genotype is known, otherwise, use a solid white
circle with the known parts of the genotype written next to the symbol.
Also, write the names and genotypes below each of the circles or
squares.
4. In 2026, a strange mutation is found in a cat which provides extra skin
between their legs and their body and allows them to glide, much like a
flying squirrel. After finding this stray cat with this unique phenotype,
Charlie decides he wants to make this cat into a new type of show breed.
Little does Charlie know that this cat already has created many kitten
offspring, with about half of his offspring also having the ability to glide.
This suggests that the ‘flyer’ phenotype is apparently autosomal
dominant. How can Charlie develop a true breeding cat? Describe the
tests that you would need to do to determine whether the flyer gene is
dominant or recessive and whether it is autosomal or sex-linked.
Describe a test to determine that a cat is true-breeding.
5. Provide evidence as to why the X and Y are not homologous. Provide
evidence as to why the X & Y are homologous.