Question

You must try to answer both questions: Cystic fibrosis (CF) is an inherited disorder that causes severe damage to the lungs, the digestive system and other organs within the body. CF affects cells that produce thin and slippery mucus and cause the secretions to become sticky and thick. CF is caused by a deletion mutation on chromosome 7. In order for a child to have cystic fibrosis they must inherit a defective gene from each of his/her parents a) Rob and Jane have four children in this order: a son (Leon), a daughter (Claire), a son with CF (Shane) and a daughter (Parmjit). Parmjit had a child with a man (Keron) and their daughter (Laura) has CF. Draw and fully label a pedigree to show this family's inheritance of CF. What mode of inheritance is cystic fibrosis? (5 marks) • • 1 mark for symbols and legend 1 mark for generations 2 marks for correctly labelling carrier and afflicted genotypes/phenotypes 1 mark for stating inheritance • [insert your photo here] b) If their youngest daughter (Parmjit) and her husband were to have another child, what is the probability that the next child would be a son with CF? Draw a punnett square to show how you came up with your answer. (3 marks) [insert your photo here] Your Name Teachers Name c) CF is caused by a deletion mutation. Scientists have found that there are three bases on chromosome 7 that have been deleted. Explain why the deletion of 3 bases may not be as devastating as the deletion of one base. Be very specific and give an example to help with your explanation. (4 marks) [insert your answer here]