Advanced Genetics Practice
Name: ______________________________________________
MONOHYBRID CROSSES
1. In rabbits, black fur (B) is dominant over brown fur (b). Create a Punnett square to analyze the cross between a
heterozygous black rabbit and a brown rabbit.
Parents’ phenotypes ___________________and ___________________
Parents genotypes _______ and ________
Offspring genotype and percentages _______________________________
Offspring phenotype and percentages _______________________________
2. In pea plants, purple flower color (P) is dominant over white flower color (p). Use a Punnett square to analyze the
cross between a homozygous purple flower and a homozygous white flower.
Parents’ phenotypes ___________________and ___________________
Parents genotypes _______ and ________
Offspring genotypes and percentages _______________________________
Offspring phenotypes and percentages _______________________________
3. Using the offspring from Question 2 above, cross two offspring together
Genotypes from Question 2 offspring _______ and ________
Phenotypes from Question 2 offspring ___________________and ___________________
New offspring genotype and percentages _______________________________
New offspring phenotype and percentages _______________________________
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PEDIGREES
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INCOMPLETE DOMINANCE
4. Snapdragons show incomplete dominance. A cross between a red snapdragon and white snapdragon gives all pink
snapdragon offspring. There are two alleles, R which is red, and W which is white. What are the three genotypes?
Red snapdragon ___________
White snapdragon ___________
Pink snapdragon ___________
5. A red snapdragon and a pink snapdragon are crossed. Use a Punnett square to analyze this cross.
Parent phenotypes ___________________and ___________________
Parent genotypes _______ and ________
Offspring genotype and percentages _______________________________
Offspring phenotype and percentages _______________________________
6. A farmer wants to make many pink snapdragons. He decides to cross two pink snapdragons. Use a Punnett Square
to analyze this cross.
Parent phenotypes ___________________and ___________________
Parent genotypes _______ and ________
Offspring genotype and percentages _______________________________
Offspring phenotype and percentages _______________________________
7. What advice would you tell the farmer? What two flowers would be better to get all pink snapdragons?
____________________________________________________________________________________
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SEX-LINKED or X-LINKED
In humans, hemophilia is a sex linked trait. Females can be normal, carriers, or have the disease. Males will either
have the disease or not (but they won’t ever be carriers)
X H X H = female, normal
X H X h = female, carrier
X h X h = female, hemophiliac
X H Y = male, normal
X h Y= male, hemophiliac
8. Show the cross of a man who has hemophilia with a woman who is a carrier.
Parent phenotypes ___________________and ___________________
Parent genotypes _______ and ________
Offspring genotype and percentages _______________________________
Offspring phenotype and percentages _______________________________
9. A woman who is a carrier marries a normal man. Show the cross. What sex will a child in the family with
hemophilia be?
Parent phenotypes ___________________and ___________________
Parent genotypes _______ and ________
Sex of child with hemophilia? _____________
10. A woman who has hemophilia marries a normal man. How many of their children will have hemophilia, and what
is their sex? __________________________________
Parent phenotypes ___________________and ___________________
Parent genotypes _______ and ________
Percentage of offspring with hemophilia ____________
Sex of offspring with hemophilia __________
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