Tortoise shell cats have variegated coat colors caused by X-inactivation and are always what?

• A. Hermaphrodites
• B. Sterile
• C. Male
• D. Female

Answer: (D)

Verified step by step guidance

1. Understand the concept of X-inactivation: In female mammals, one of the two X chromosomes in each cell is randomly inactivated during early embryonic development. This process is known as X-inactivation and leads to the formation of a Barr body.
2. Recognize the genetic basis of tortoiseshell coat color: The variegated coat color in tortoiseshell cats is due to the presence of two different alleles on the X chromosomes, one for black fur and one for orange fur. X-inactivation causes different patches of fur to express different alleles.
3. Consider the genetic makeup required for tortoiseshell coloration: Since the coat color is determined by alleles on the X chromosome, a cat must have two X chromosomes to exhibit the tortoiseshell pattern. This means the cat is genetically female (XX).
4. Evaluate the options given: Hermaphrodites, Sterile, Male, Female. Based on the genetic requirement for two X chromosomes, the correct answer is Female.
5. Conclude that tortoiseshell cats are almost always female due to the necessity of having two X chromosomes for the expression of the variegated coat pattern.