More Dihybrid Crosses

Name ________________________________
In rabbits, grey hair (G) is dominant to white hair. Also, black eyes (B) are dominant to red eyes.
A male rabbit with red eyes that is heterozygous for fur mates with a white haired rabbit that is
heterozygous for eyes. Complete the following square and answer the questions:
Phenotypes
GG –
Gg –
gg –
BB –
Bb –
bb –
Square
a.
How many out of 16 have gray fur and black eyes? ________
b.
How many out of 16 have gray fur and red eyes? ________
c.
How many out of 16 have white fur and black eyes? ________
d.
How many out of 16 have white fur and red eyes________

An aquatic arthropod called a Cyclops has antennae that are either smooth or barbed. The allele
for barbs (B) is dominant over smooth (bb). In the same organism Non-resistance to pesticides
(N) is dominant over resistance to pesticides (nn). Fill in the “key” below. A Cyclops that is
resistant to pesticides and has smooth antennae is crossed with one that is heterozygous for
both traits.
Phenotypes
BB –
Bb –
bb –
NN –
Nn –
nn–
Square
What are the genotypic and phenotypic ratios of the offspring?