In: Biology
Ans A) the Pedigree of given family from the given information is as below :
Alleles = F = Dominant = normal or unaffected ; f = recessive = affected in ff (Homozygous Recessive Condition).
Ans B) Probability that this woman and her husband will have a child with Cystic Fibrosis ( ff). In the question the information about their parents Genotype is also given as either of woman's Parents have a recessive allele (f) and the husband's mother is Homozygous for Dominant allele of CFTR gene = FF. The husband's Father could be FF or Ff as he is healthy and has an elder brother who died of Cystic Fibrosis. So, he can be FF or Ff and hence with wife FF he can have child with Genotypes FF or FF and Ff. We have to find the Probability of having affected child of woman and husband then husband will be a carreir by Probability 1/2 as ( 1 = Ff ; 2 = FF + Ff).
Mother carrier by = 2/4 or 1/2
Father = 1/2
Child can be affected by = 1/4
Probability of affected child = 2/4 * 1/2 * 1/4
= 1/16.