Final answer:
The varying coat color phenotypes among offspring of a grey and Himalayan rabbit are due to multiple alleles and a dominance hierarchy of rabbit coat color genes.
Step-by-step explanation:
The different phenotypes of the offspring from a grey rabbit and a Himalayan rabbit can be explained by the concept of multiple alleles for the rabbit coat color gene. In rabbits, there are four alleles for the c gene which determine coat color: the wild-type brown fur (C+C+), the chinchilla phenotype with black-tipped white fur (cchcch), the Himalayan phenotype with black fur on extremities and white fur elsewhere (chch), and the albino or colorless phenotype with white fur (cc). Each allele has a different dominance hierarchy, where wild-type is dominant over all the others, chinchilla is incompletely dominant over Himalayan and albino, and Himalayan is dominant over albino.
The Himalayan allele produces a temperature-sensitive gene product that results in pigment only in the cooler parts of the body—like ears, nose, feet, etc. This concept is similar to the gene that causes the distinctive coloration in Siamese cats. The presence of dark grey, Himalayan, and solid white offspring suggests a mix of these alleles carried by the parents, as expressed in the variety of offspring coat colors.
Furthermore, in certain environments, such as a rocky or snowy habitat, the coat color can provide camouflage for the rabbits leading to diversifying selection based on the most advantageous phenotype. Consequently, in different environmental contexts, certain phenotypes like the Himalayan or solid white may be naturally selected over others due to their camouflage benefits, influencing the frequency of alleles within a population.