Question

The pedigree chart below shows the individuals in a family who exhibit a certain trait. Based on the information in the chart, what conclusions can be drawn?

A diagram of a pedigree chart. At the top of the chart are two individuals, one indicated by a green circle and one by a green square. At the next level down, the green circle is paired with a black square and the green square is paired with a black circle. From the green circle, black square pairing, there are three offspring, a green circle, a green square, and a black square. From the green square, black circle pairing, there are eight offspring, three black circles and four black squares. Two of the black squares are identical twins. One of the black circles is paired with another black square. This pairing produced one green circle.

Key:
Circle—Female
Square—Male
Green—Exhibits trait

It is a codominant trait.
It is a dominant trait.
Individual 10 is homozygous for the trait.
Individual 10 is heterozygous for the trait.

Answer 1

Individual 10 is heterozygous for the trait.

The pedigree chart as described contains, I, II, and III generations.

• The first option is incorrect as both parents are not co-dominant due to not showing homozygous genes exhibiting the trait.
• The second option is also incorrect because if the individuals showed dominance traits in III - 4 and III - 5, they would not be in black square and circle
• Individual 10 male is in black and hence does not show the trait, if the III-10 did, then the square would be green square instead of black. So incorrect
• The last option is correct. Individual 10 is heterozygous as it appears to be having a black square but got traits from the individual's father who is green homozygous and from homozygous mother.

Answer 2

Answer: The answer is “it is a dominant trait”

Explanation:

It’s B