Final answer:
In cats with the colorpoint pattern, both parents must carry at least one allele for the trait due to incomplete dominance. A solid black cat mated with a colorpoint cat yielding 50% colorpoint offspring indicates the black cat is heterozygous for colorpoint. Cat coat color inheritance is sex-linked, and calico cats demonstrate codominance.
Step-by-step explanation:
If a cat has the colorpoint pattern, which is a result of incomplete dominance, we can conclude that both parents carried the gene for this trait. Each parent must have had at least one allele for colorpoint to pass it on, meaning they could have been either heterozygous (one allele for colorpoint, one for solid color) or homozygous (both alleles for colorpoint) for the trait. The exact genotype would depend on the phenotypes of the parents.
Regarding the second part, if a cat with the colorpoint pattern is crossed with a solid black cat and half of the kittens have the colorpoint phenotype, it suggests that the solid black cat was heterozygous for the colorpoint trait. Using a Punnett square, we can determine the probability of the potential genotypes and phenotypes of the offspring. The results of this cross would likely show a 1:1 ratio of colorpoint to solid black offspring, indicating the solid black parent carries one allele for the colorpoint trait and one for the solid black trait.
Coat color in cats, specifically black, yellow, or calico, is an example of sex-linked inheritance, as the coat color gene is located on the X chromosome. Moreover, calico coloration is due to a phenomenon known as codominance, where both the black and yellow alleles are expressed in the phenotype.