Download Dihybrid Worksheet

Dihybrid Worksheet
Name:___________________________________
Period: _________
Date:________________
SHOW ALL WORK! KEEP YOUR WORK NEAT!
1. Genotype Practice – In bunnies, black is dominant to white. Rough is dominant to smooth.
Give the genotype for each of the following:
a. Homozygous black, smooth bunny: _____________
d. White, smooth bunny: _____________
b. Heterozygous black-rough bunny: _____________
e. Homozygous black-rough bunny: _____________
c. White, homozygous rough bunny: _____________
f. White, heterozygous rough bunny: _____________
2. Gamete Combination Practice. Give the gamete combination for each genotype.
a. AATt _____, _____, _____, _____
c. aatt _____, _____, _____, _____
b. AaTT _____, _____, _____, _____
d. AAtt _____, _____, _____, _____
3. In hamsters, black coat is dominant to white coat and rough coat is dominant to smooth coat. Two
heterozygous black-rough coated hamsters where mated.
a. Give the genotype cross: ____________x____________
b. Complete the punnett square:
c. What would be the phenotype ratio of the F1 generation?
____ Black-Rough : ____ Black-Smooth : ____ White-Rough : ____ White-Smooth
d. What would be the genotype ratios of the F1 generation?
___ BBRR : ___ BBRr : ___ BBrr : ___ BbRR : ___ BbRr : ___ Bbrr : ___ bbRR : ___ bbRr : ___ bbrr
4. In garden peas, axial flower position is dominant and terminal flower position is recessive; tall vine is dominant
and short vine recessive. A plant known to be purebred for tall vine and axial flowers is crossed with a plant
having short vines and bearing terminal flowers.
a. Give the genotype cross: ____________x____________
b. Complete the punnett square:
c. What is the phenotype of the offspring? ___________________________
d. What is the genotype of the offspring? ___________
e. Cross the F1 individuals to determine the F2 generation.
f. What would be the phenotype ratio of the F1 generation?
____________________________________________________________________________________________________
g. What would be the genotype ratios of the F1 generation?
____________________________________________________________________________________________________
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Problem solving…think outside the square
5. In dogs, wirehair is a dominant trait, smooth hair is recessive. Two wire-haired dogs produce a male puppy
that is wire-haired. To find out most quickly whether he carries the allele for smooth hair, he should be mated to
what type of female?
6. In a certain animal, a breed is known that always has a hairy tail; another breed is known that always has a
naked tail. How would you determine which trait is dominant?
7. In cocker spaniels, black is a dominant trait (B), red is recessive (b). Solid color is dominant (S) and white
spotting is recessive (s). A red male was mated to a black-and-white female. They had five puppies as follows: 1
black, 1 red, 1 black-and-white, and 2 red-and-white. What are the genotypes of the parents?
8. Two plants having red flowers are mated. When their F1 offspring are studied, it is found that 95 have red
flowers and 31 have white flowers. What is the genotype of the parents and diagram a cross to support your
answer.
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