Case Study: Joshua and Bella -Joshua and Bella have a son named Ian.
-Ian has been diagnosed with cystic fibrosis (CF).
-Joshua and Bella are both healthy.
-Bella’s parents are both healthy.
-Joshua’s parents are both healthy.
-Joshua’s sister, Sara, has cystic fibrosis.

1. Draw a pedigree that shows all the family members. Use circles to represent the females, and squares to represent the males. Shade in the circles or squares representing the individuals who have cystic fibrosis. (I think both of Joshua's parents are carriers, but how would I show Joshua as a carrier X^rY? Also, would Ian's mom be a carrier?)

2. Cystic fibrosis is controlled by a recessive allele. Ian has cystic fibrosis. So does Joshua’s sister, Sara. Determine their genotypes and write them next to their pedigree symbol above.

3. Figure out what genotypes Joshua and Bella have and write them next to their symbols in the pedigree.

4. Determine the genotypes of all the other family members and fill them next to their symbols in the pedigree. If more than one genotype is possible, write in both genotypes.

5. If Josh also has a brother. What is the probability that he has cystic fibrosis? Explain with words and use of Punnett squares.