The first cloned cat, called Carbon Copy, was a calico, but she looked significantly different from her female parent. Which of the following best explains the reason for the differences?
A) The cloning was done poorly and some contaminating cat DNA became part of Carbon Copy's genome.
B) Fur color genes in cats are determined by differential acetylation patterns that reset when cloned.
C) Cloned animals have been found to have a higher frequency of transposon activation.
D) X chromosome inactivation in the embryo is random and produces different patterns.

Question

Quizplus · Accepted Answer

X chromosome inactivation in female mammals, including cats, is a random process that occurs in the early stages of embryonic development. Since calico cats' fur color is linked to genes on the X chromosome, and each cell randomly inactivates one of its two X chromosomes, cloned calicos can look significantly different from their parents despite having the same genetic material. This is because the pattern of X chromosome inactivation in the clone can differ from that of the parent, leading to different expression of fur color genes.

The First Cloned Cat, Called Carbon Copy, Was a Calico