Question

Given above is a pedigree chart of a family with five children. It shows the inheritance of attached earlobes as opposed to the free ones. The squares represent the male individuals and circles the female individuals. Which one of the following conclusions drawn is correct?

• A. The parents are homozygous recessive.
• B. The trait is Y linked.
• C. The parents are homozygous dominant.
• D. The parents are heterozygous.

Answer 1

The correct option is D The parents are heterozygous.

• In the given pedigree chart, parents from the 1st generation are normal, yet they transfer disease to their children in the second generation. This would be possible only if both parents are carriers (heterozygous) for recessive inheritance.

So the correct answer is option D.