BotanyGiven ahead is a pedigree chart of a family with five children. It shows the inheritance of attached ear-lobes as opposed to the free ones. Which of the following conclusions drawn is correct?

Given ahead is a pedigree chart of a family with five children. It shows the inheritance of attached ear-lobes as opposed to the free ones. Which of the following conclusions drawn is correct?

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

Solution:

The parents are heterozygous. Only then there is a possibility that parents themselves are not exhibiting the trait but two of their progeny are. Two recessive alleles have to come together to express phenotypically.

All males will be affected, if it is Y-linked.

If both parents are homozygous dominant, all the children would have been affected.