Describe a specific example of a cross between two parents, each homozygous for
ID: 824554 • Letter: D
Question
Describe a specific example of a cross between two parents, each homozygous for different traits, which would result in a phenotype that is distinct from either parental phenotype.
1. Indicate the genotype and phenotype of each parent and the offspring.
2. Indicate the inheritance pattern of the character described.
Rules:
1. You may use imaginary organisms. Crosses involving dragons, hobbits, and unicorns are allowed.
2. The distinct offspring phenotype may not be a result of mutations.
3. Describe a cross that is not described in your textbook.
Explanation / Answer
Standard dihybrid crosses (which is what you get whenever you cross parents that are heterozygous for 2 traits, e.g. AaBb) always produce a 9:3:3:1 ratio, where the 9 (out of 16) is the ratio of offspring expressing both dominant traits, 1 (out of 16) is the ratio of offspring expressing both recessive traits and the 3s (out of 16) is the ratio of offspring expressing one dominant and one recessive trait.