Normally, only female cats have the tortoiseshell phenotype because
A) the males die during embryonic development.
B) a male inherits only one allele of the X-linked gene controlling hair color.
C) the Y chromosome has a gene blocking orange coloration.
D) only males can have Barr bodies.
E) multiple crossovers on the Y chromosome prevent orange pigment production.

Question

Quizplus · Accepted Answer

The tortoiseshell phenotype is produced by an X-linked gene that controls hair color. Females have two X chromosomes, so they can inherit two different alleles that may produce different color patches. In contrast, males have only one X chromosome, and they inherit only one allele from their mom. Therefore, male cats can have orange or black fur, but not both in patches. They are either solid orange or black or a mosaic of both but never in distinct patches. This is the same reason why calico cats are mostly female as well.

Normally, Only Female Cats Have the Tortoiseshell Phenotype Because