Genetic Crosses that Involve 2 Traits -- Biology 2

In rabbits, grey hair is dominant to white hair. Also in rabbits, black eyes are dominant to red eyes.

GG = gray hair Gg = gray hair gg = white hair

BB = black eyes Bb = black eyes bb = red eyes

1. What are the phenotypes (descriptions) of rabbits that have the following genotypes:

Ggbb ____________________ ggBB ________________________
ggbb ____________________ GgBb _________________________

2. A male rabbit with the genotype GGbb is crossed with a female rabbit with the genotype ggBb The square is set up below. Fill it out and determine the phenotypes and proportions in the offspring.

How many out of 16 have grey fur and black eyes? ____

How many out of 16 have grey fur and red eyes? _____

How many out of 16 have white fur and black eyes? ____

How many out of 16 have white fur and red eyes? _____

3. A male rabbit with the genotype GgBb is crossed with a female rabbit with the genotype GgBb The square is set up below. Fill it out and determine the phenotypes and proportions in the offspring.

 

How many out of 16 have grey fur and black eyes? ____

How many out of 16 have grey fur and red eyes? _____

How many out of 16 have white fur and black eyes? ____

How many out of 16 have white fur and red eyes? _____

4. Set this one up on the back of this page. A male rabbit with genotype GgBb x with a female rabbit with genotype ggbb. Show the Punnett square and the expected offspring and their proportions.

---

Resources on Genetics

Rabbit Genetics - Long ears and Black Noses

Codominance and Incomplete Dominance – practice genetics on roan cows and pink flowers

Cow Genetics – roan coloration and horns, also includes a two-trait cross