Question

If the mottled coloring of calico cats is due to X-chromosome inactivation, which of the following statements will be TRUE?

A. The mottled colors in the cat will be prominent only during a specific time of the year.
B. Female calico cats will display the same color pattern as their mother.
C. The mottled color is due to X chromosomes repeatedly switching back and forth between active and inactive states during development.
D. The mottled color suggests that in a population of cells both X-chromosomes are active.
E. The male cats (containing one X chromosome) will not show the mottled coloring.

Answer 1

The mottled color suggests that in a population of cells both X-chromosomes are active.

Step-by-step explanation:

The correct statement is D. The mottled color suggests that in a population of cells both X-chromosomes are active. The mottled coloring in calico cats is due to X-chromosome inactivation during embryonic development. In female cats, one of the two X chromosomes is randomly inactivated in each cell, resulting in a tortoiseshell pattern if the cat has two different alleles for coat color. This means that each cell in the cat's body can have different X-chromosomes inactivated, resulting in mottled colors.