Given below is a pedigree in which the inheritance of an autosomal dominant disease gene is being followed. Linked to the disease gene (3 cM = 3% recombination away) is a RFLP marker with 2 alleles (5 kb and 3 kb). Given the DNA marker compositions for children II.2 and II.3 (for whom the disease gene inheritance is unknown),
(a) What is the probability that the child II.2 will be diseased (Dd)? (b) What is the probability that the child II.3 will be disease-free (dd)?
dd=female unaffected= I.1=5kb and 3 kb
Dd= male affected= I.2= 5kb and 3kb
Dd= affected son= II.1= 3kb
II.3 = 5kb and 3kb