2. Mendel's Laws of Inheritance

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 with 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

What do the results of these crosses suggest about the inheritance of color and tail fin shape in goldfish?

Which of the following Mendel's postulates states that alleles separate in the formation of gametes?

Breeding two pure-lines of yellow-seeded flowers will always produce yellow-seeded offspring

What is the official genetics term for the second generation of offspring?

How was Mendel able to derive postulates concerning the behavior of 'unit factors' during gamete formation when he could not directly observe them?