2. A male rabbit with the genotype GGbb is crossed with a female rabbit with the genotype ggBb
The square is set up below. 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?

- Half (8/16) of the offspring will have gray fur and black eyes.

- Half (8/16) of the offspring will have gray fur and red eyes.

- None (0/16) of the offspring will have white fur.

Explanation:

For the purposes of this question, we will assume the following notation for the involved alleles:

G: gray fur (dominant), g: white fur (recessive).

B: black eyes (dominant), b: red eyes (recessive).

A GGbb rabbit may only produce one type of gametes, namely Gb.

A ggBb rabbit may produce either gB or gb gametes.

Since not all theoretical combinations are present, the resulting Punnett square may be simplified as follows:

       |     Gb

——-+-————

gB   |   GgBb

——-+-————

gb   |   Ggbb

As seen above, 100% of the offspring will have a Gg genotype (resulting in gray fur). As for eye color, half of them will have a Bb genotype (resulting in black eyes) whereas the other half will have a bb genotype (red eyes).

amber has allowed scientists to study dna that has been preserved over millions of years.

a tetrad is the foursome during meiosis made by two homologous chromosomes that have each already replicated into a pair of sister chromatids.