3 Shown is a pedigree depicting a family in which some membe

3. Shown is a pedigree depicting a family in which some members are affected by a fully -penetrant genetic condition. a) Determine the mode of inheritance of this condition (possibilities are: Autosomal Dominant, Autosomal Recessive, X-linked Dominant, X-linked Recessive, or Y-inked). Only one is possible. b) For each mode of inheritance that you were able to rule out, circle a parent-child relationship on the pedigree that allowed you to exclude that particular mode of inheritance as a possibility. Next to each of your drawn circles, write a brief one-sentence explanation of why that evidence is sufficient to rule out the mode of inheritance in question. c) Label all individuals whose genotype cannot be predicted with 100% certainty with a OTO

Solution

a) The mode of inheritance is recessive because in the second generation any one of the parent is carrier, since they are normal and among, their three children, one of the child is affected. This mode of inheritance could be explained by autosomal recessive mode than X-linked recessive mode, because it has been seen when the mother is affected in the first generation, one of her son is normal. This could be explained by autosomal recessive mode than X-linked recessive mode.

b) Autosomal Dominant and  X-linked Dominant are ruled out because there are carriers (affected son of the when both parents are normal on the first generation). X-linked recessive is ruled out because it has been seen when the mother is affected in the first generation, one of her son is normal (2nd marriage of first genearation).

c) In the second generation, the normal individuals who are married, their genotype cannot be predicted with 100% certainty because one of them is certainly a carrier but it could be any one of them or both could be carriers.