Question

Given pedigree shows that the trait is inherited as autosomal dominant. Trace the genotype of mother and father.

(A) Father AA, Mother aa
(B) Father AA, Mother Aa
(C) Father aa, Mother AA
(D) Father aa, Mother Aa

Answer 1

Hint: The study of a specific trait that is passed down from one generation to the next is called pedigree analysis. Knowing whether a specific characteristic is genuinely inherited or not, as well as the trait's inheritance pattern, is helpful.

Complete Step by Step Answer:
A pedigree offers a visual representation of the makeup and health history of a family. When obtaining a pedigree, it's crucial to be methodical and use conventional symbols and arrangements. A pedigree aids in identifying individuals and families who are more likely to have genetic illnesses. In the above question, pedigree is for autosomal dominant, the darkened boxes represent that the person is diseased. In parent generation, father is not affected so it will have genotype of ‘aa’ and the mother is affected so it can have genotype ‘AA’ or ‘Aa’. Now, coming on to progeny the male child is not diseased so it will also have a genotype of ‘aa’ this means one allele of unaffected gene will come from father and one from the mother, so in mother one allele of two will be disease free. This means genotype of mother is ‘Aa’.
Therefore genotype of father is ‘aa’ and genotype of mother is ‘Aa’.
So, option (D) is the correct answer.

Note: Linked genes are split apart by crossing across. The frequency of crossing over ranges from 0 to 50%, however it might be higher than 50%. Additionally, crossing over ensures that both parental and recombinant types will exist in equal amounts in a test cross.