What genotype do both parents of the Himalayan rabbits have?

To understand why both parents of Himalayan rabbits must have the genotype indicated in the correct answer, it's essential to consider the specifics of the gene responsible for the Himalayan coat color.

Himalayan rabbits display a unique coat pattern characterized by dark coloration at the extremities (ears, nose, paws, and tail) while the rest of the body remains white. This trait is influenced by a gene that is temperature-sensitive; the responsible gene is a form of the gene for albinism, denoted as 'c.' The Himalayan phenotype arises from the presence of a specific allele in a heterozygous condition.

When analyzing the genotypes, the 'c' allele is associated with absence of pigment (albino), while the 'C' allele allows for normal pigmentation. For the Himalayan trait to appear, the rabbits must carry at least one 'c' allele and at least one 'C' allele. This means they have to be heterozygous (cC) or homozygous recessive (cc), but neither would result in the full Himalayan pattern.

The correct genotype combination mentioned indicates that both parents possess 'ch' alleles that are part of a more complex structure associated with temperature sensitivity. Specifically, 'c' here denotes a recess