Answer :
Answer:
The correct answer is: X-inactivation.
Explanation:
Calicos are a type of cat with three colors in their fur: white, black and orange. The reason behind this particular fur is plain genetics.
The determination of the colors on the fur of cats is always linked to the X chromosome (of the sexual pair).
In female mammals, since there are two X chromosomes (one from the mother and one from the father), there is one that is inactivated randomly in every cell - this is called X-inactivation. But because this inactivation is random, there will be cells with one of the X chromosomes inactivated and cells with the other X chromosome inactivated. Since fur color is linked to this chromosome, it means that this cat will have some cells that express one color and some cells that express the other one.
For this fur pattern to happen the cat must have 2 X chromosomes, so calico cats are almost exclusively female (male cats have 1 X chromosome and Y chromosome).
Answer:
Nondisjunction
Explanation:
According to the glossary, "Nondisjunction is a mutation that causes chromosome separation during cell division to fail. As a result, one daughter cell will have an extra chromosome, and the other will be missing a chromosome." This would make sense for Calix, because Calix's mass of DNA per cell is higher than usual, and Nondisjunction would explain the difference in mass. We also know that it cannot be a point mutation because "Point mutations do not change the mass of DNA." On the other hand, it cannot be chromosomal rearrangement because the mass of Calix's DNA per cell would not match up with what it would be if Calix had a chromosomal rearrangement.