Date _______
Dihybrid Crosses
Name ____________________
1. In the diagram above, label the gametes and the homologous chromosomes.
2. What process is being shown above? ________________________________
3. What is the difference shown between diagram 1 and diagram 2?
___________________
_____________________________________________________________________
_____________________________________________________________________
4. How many alleles are in the diploid cells? ______________________________________________
5. How many alleles are in the gametes? ________________________________________________
6. In your own words, explain what is meant by independent assortment?
_____________________________________________________________________
_____________________________________________________________________
7. In cats, red hair (R) is dominant to white hair (r) and
yellow eyes (Y) are dominant to green eyes (y). A cat
with homozygous red hair and has green eyes is crossed
with a cat who is heterozygous for red hair and
heterozygous for yellow eyes.
Genotype Ratio:
_____________
_____________
_____________
_____________
Date _______
Dihybrid Crosses
Name ____________________
8. In poodles, black is due to a dominant factor (B), and white to its recessive allele (b). Droopy ears is
a dominant factor (D) and pointed ears are recessive (d). A white male with droopy ears was mated
to a black female with pointed ears. They have 4 pups as follows: one black with droopy ears, one
white with droopy ears, one black with pointed ears and one white with pointed ears.
a) What is the genotype of the parents?
Gametes
Give the genotype of
the puppies:

Black, droopy ears
_____________

White, droopy ears
_____________

Black, pointed ears
_____________

White, pointed ears
_____________
_
9. In cows, black is due to a dominant factor (B) and red to its recessive allele (b). Tail hair is due to a
dominant factor (T) and hairlessness to its recessive allele (t). If a homozygous black hairless is
mated to a homozygous red hairy, what will be the appearance of the F1 generation?
a) What is the genotype of the parents? _____________________________________________
Gametes
b) What is the phenotype ratio of the F1 generation?