Chapter 4, Problem 20PDQ

In cattle, coats may be solid white, solid black, or black-and- white spotted. When true-breeding solid whites are mated with true-breeding solid blacks, the F₁ generation consists of all solid white individuals. After many F₁ $\times$ F₁ matings, the following ratio was observed in the F₂ generation:

12/16 solid white

3/16 black-and-white spotted

1/16 solid black

Explain the mode of inheritance governing coat color by determining how many gene pairs are involved and which genotypesyield which phenotypes. Is it possible to isolate a true-breeding strain of black-and-white spotted cattle? If so, what genotype would they have? If not, explain why not.