Question

Two pedigrees (P and Q) are given, Individual-$1$ in $F_0$ generation of pedigree Q is not a carrier of the trait. Circles in the pedigree represent females and squares represent males. Filled shapes indicate affected individuals while unfilled shapes indicate unaffected individuals.
Assuming Mendelian inheritance and complete penetrance of the traits, choose the correct statement(s) from the following.

• A. Both pedigrees P and Q represent autosomal recessive traits
• B. Both pedigrees P and Q represent autosomal dominant traits
• C. Pedigree P represents an autosomal recessive trait and Q represents an autosomal dominant trait
• D. Pedigree P represents an X-linked recessive trait and Q represents an autosomal recessive trait

Answer 1

The correct option is C Pedigree P represents an autosomal recessive trait and Q represents an autosomal dominant trait

From the given pedigree charts, following observations can be made:

For pedigree P:

1. Affected offspring are borne to unaffected parents.

2. The trait is skipping generations i.e., not present in every generation.

3. The trait is occurring in male and female individuals with an equal frequency.

This shows that pedigree P represents Autosomal recessive trait.

For pedigree Q:

1. Affected offspring are borne to affected parents.

2. Unaffected parents are not transmitting the trait to offspring.

3. When one of the parents is affected, approximately half of the offspring are affected.

4. The trait is occurring in male and female individuals with an equal frequency.

This shows that pedigree Q represents Autosomal dominant trait.

So, the correct answer is C.