What is the expected genotypic ratio from a dihybrid cross?

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Q: What is the expected genotypic ratio from a dihybrid cross?

Solution: The expected genotypic ratio from a dihybrid cross is 9:3:3:1, representing the combinations of two traits.

Steps: 7

Step 1: Understand what a dihybrid cross is. It involves two traits, each with two alleles.
Step 2: Identify the alleles for each trait. For example, let's say Trait 1 has alleles A and a, and Trait 2 has alleles B and b.
Step 3: Create a Punnett square for the dihybrid cross. This will be a 4x4 grid because there are four combinations of alleles from each parent.
Step 4: Fill in the Punnett square with all possible combinations of the alleles from both traits.
Step 5: Count the different genotypes that appear in the Punnett square.
Step 6: Determine the ratio of each genotype. You will find 9 combinations of the dominant traits, 3 combinations of one dominant and one recessive trait, 3 combinations of the other dominant and recessive trait, and 1 combination of both recessive traits.
Step 7: Write the final expected genotypic ratio as 9:3:3:1.