Discussion:
Mendelian inheritance
Questions
Question 1.
A. When mating/crossing a white pure-breeding elephant, with a black pure-breeding elephant, Jen expected offspring that were entirely white. Why?
B. Explain by showing genotypes of parents and progeny.
C. If, instead, the progeny were gray, give a possible explanation.
D. If, instead, Jen mated two heterozygous white elephants, what would be the expected phenotypes if this trait followed basic Mandelian genetics? Explain your answer.
E. If the phenotypes were in a 1:2:1 phenotypic ratio of white:gray:black, give a possible explanation for this result.
What explanation would be given if the progeny from such a cross in c. give all white elephants.
2. For each of the following, give a brief description:
A. pleiotrophy
B. expressivity
C. sex-limited trait
D. multiple alleles
Question3.
A. Why would you suspect that a trait is X-linked?
B. Why would you suspect that a trait is Y-linked?
C. Draw a Punnett square to show how a daughter could inherit red/green color blindness.
4. A person with blood type B (whose parents were types O and AB respectively) mates with a person with type AB.
A. What are the expected blood types (phenotypes) and their proportions in their children?
B. What are the expected genotypes at this locus and their proportions in their children?
C. Pretend that instead of being codominant, A, B, and O were sequentially dominant, with A dominant over B and B dominant over O. What would the phenotypes and their proportions be in children from such a mating?
Question5.
A. Describe in detail what is meant by a quantitative trait? Give an example and include in your answer how it differs from a "Mendelian trait."
B. What is meant by the term "heritability"?
C. Sketch the variation of leaf size you might see in trees in a forest. Assume that leaf size is a quantitative trait.