Assignment

1. Compare and contrast mitosis and meiosis (include at least 3 comparisons and 3 differences).

2. A woman who is a carrier for cystic fibrosis has children with a man that has cystic fibrosis.

a. What are the parental genotypes?

b. What F1 phenotypic and genotypic ratios are produced from this cross? (Show your Punnett Square)

c. Diagram the F2 results. (Show your Punnett Square).

3. R codes for red flower color and r codes for white flower color.

a. What color would Rr be if R has complete dominance?

b. What color would Rr be if R and r are codominant?

c. What color would Rr be if R has incomplete dominance?

4. Red-green colorblindness is an X-linked recessive mutation. A colorblind female has children with a normal male.

a. What are the parental genotypes? (Hint: the sex of the parent is important)

b. What F1 phenotypic and genotypic ratios are produced from this cross? (Show your Punnett Square)

5. In a dihybrid cross between RrTt and RRtt, what are the genotype and phenotype ratios of the offspring, assuming R and T are dominant? R codes for round seed, while r codes for wrinkled seed. T codes for tall height, while t codes for short height. (Show your Punnett Square). Hint: Do the Punnett Square for each trait separately and then combine them using the branch diagram as shown in Figure 3.11

6. The pedigree below traces the inheritance of alkaptonuria, a biochemical disorder. Affected individuals, indicated here by the filled-in circles and squares, are unable to break down a substance called alkapton, which colors the urine and stains body tissues.

a. Does alkaptonuria appear to be caused by a dominant or recessive allele? Explain.

b. What is George's phenotype?

c. Is it possible for Daniel to have a child with alkaptonuria? Explain.

d. How would knowing the pattern of inheritance influence the treatment plan for this disease?

7. Mary has type A blood and her husband (John) has type B blood. John's parents both had type AB. Mary and John have three children, one with type A, one with type AB, and one with type B. Relatives suspect that one of the children was adopted.

a. What are Mary and John's blood genotypes?

b. Which child was adopted? Explain your answer.