An experienced goldfish breeder receives two unusual male goldfish. One is black rather than gold, and the other has a single tail fin rather than a split tail fin. The breeder crosses the black male to a female that is gold. All the F₁ are gold. She also crosses the single-finned male to a female with a split tail fin. All the F₁ have a split tail fin. She then crosses the black male to F₁ gold females and, separately, crosses the single-finned male to F₁ split-finned females. The results of the crosses are shown below.
Black male x F₁ gold female:
Gold 32
Black 34
Single-finned male x F₁ split-finned female:
Split fin 41
Single fin 39
Use chi-square analysis to test your hereditary hypothesis for each trait.
3. Extensions to Mendelian Inheritance
Chi Square Analysis