In rabbits, a series of multiple alleles controls coat color in the following way: C is dominant to all other alleles and causes full color. The chinchilla phenotype is due to the c^ch allele, which is dominant to all alleles other than C. The c^h allele, dominant only to (albino), results in the Himalayan coat color. Thus, the order of dominance is C > c^ch > c^h > c^a. For each of the following three cases, the phenotypes of the P₁ generations of two crosses are shown, as well as the phenotype of one member of the F₁ generation.For each case, determine the genotypes of the P₁ generation and the F₁ offspring, and predict the results of making each indicated cross between F₁ individuals.

Two genes interact to produce various phenotypic ratios among F₂ progeny of a dihybrid cross. Design a different pathway explaining each of the F₂ ratios below, using hypothetical genes R and T and assuming that the dominant allele at each locus catalyzes a different reaction or performs an action leading to pigment production. The recessive allele at each locus is null (loss-of-function). Begin each pathway with a colorless precursor that produces a white or albino phenotype if it is unmodified. The ratios are for F₂ progeny produced by crossing wild-type F₁ organisms with the genotype RrTt.

9/16 dark blue : 6/16 light blue : 1/16 white

Flower color in snapdragons results from the amount of the pigment anthocyanin in the petals. Red flowers are produced by plants that have full anthocyanin production, and ivory-colored flowers are produced by plants that lack the ability to produce anthocyanin. The allele An1 has full activity in anthocyanin production, and the allele An2 is a null allele. Dr. Ara B. Dopsis, a famous genetic researcher, crosses pure-breeding red snapdragons to pure-breeding ivory snapdragons and produces F₁ progeny plants that have pink flowers. He proposes that this outcome is the result of incomplete dominance, and he crosses the F₁ to test his hypothesis. What phenotypes does Dr. Dopsis predict will be found in the F₂, and in what proportions?

The coat color in mink is controlled by two codominant alleles at a single locus. Red coat color is produced by the genotype R₁R₁, silver coat by the genotype R₁R₂, and platinum color by R₂R₂. White spotting of the coat is a recessive trait found with the genotype ss. Solid coat color is found with the S– genotype.

Two crosses are made between mink. Cross 1 is the cross of a solid, silver mink to one that is solid, platinum. Cross 2 is between a spotted, silver mink and one that is solid, silver. The progeny are described in the table below. Use these data to determine the genotypes of the parents in each cross.