Copy of DNU: Day 1 Independent: Dihybrid Crosses - 2023 (1/13/2025)

In rabbits, gray (G) is dominant to white hair (g). Also in rabbits, black eyes (B) are dominant to red eyes (b). The letters below represent the possible genotypes of the rabbits.

What is the phenotype of a rabbit that has the genotype "Ggbb"?

In rabbits, gray (G) is dominant to white hair (g). Also in rabbits, black eyes (B) are dominant to red eyes (b). The letters below represent the possible genotypes of the rabbits.

What is the phenotype of a rabbit that has the genotype "ggBB"?

In rabbits, gray (G) is dominant to white hair (g). Also in rabbits, black eyes (B) are dominant to red eyes (b). The letters below represent the possible genotypes of the rabbits.

What is the phenotype of a rabbit that has the genotype "ggbb"?

In rabbits, gray (G) is dominant to white hair (g). Also in rabbits, black eyes (B) are dominant to red eyes (b). The letters below represent the possible genotypes of the rabbits.

What is the phenotype of a rabbit that has the genotype "GgBb"?

How many different gametes can each parent produce?

How many different gametes can each parent produce?

Scenario #1: In a rare species of tree frog, green skin is dominant to blue skin and long tongues are dominant to short tongues. A homozygous green-skinned tree frog that is heterozygous for having a long tongue is crossed with a blue-skinned tree frog that has a short tongue.

Question: What is the probability of having offspring that are heterozygous for both traits?

Scenario #2: In giraffes, long necks are dominant to short necks and spots are dominant to no spots. A heterozygous long neck giraffe without spots mates with a short neck giraffe who is heterozygous for having spots.

Question: What is the probability of having a short neck giraffe with spots?

Scenario #3: In penguins, happy feet is dominant to sad feet and singing is dominant to no singing. A penguin that is heterozygous for both happy feet and singing mates with a penguin that has sad feet and cannot sing.

Question: What is the probability of having a penguin with happy feet who does not sing?

Scenario #4: In humans, being right-handed is dominant to being left-handed and having brown eyes is dominant to having blue eyes. A man who is heterozygous for both traits "falls in love" with a woman who is also heterozygous for both traits.

Question: What is the expected phenotypic ratio from this dihybrid cross?