In a dihybrid cross, what is the expected phenotypic ratio of the offspring?
Practice Questions
Q1
In a dihybrid cross, what is the expected phenotypic ratio of the offspring?
1:1
3:1
9:3:3:1
1:2:1
Questions & Step-by-Step Solutions
In a dihybrid cross, what is the expected phenotypic ratio of the offspring?
Step 1: Understand what a dihybrid cross is. It involves two traits, each with two alleles.
Step 2: Identify the traits being studied. For example, let's say we are looking at flower color (purple vs. white) and seed shape (round vs. wrinkled).
Step 3: Determine the genotypes of the parents. For example, one parent could be homozygous for both traits (PPRR) and the other could be homozygous for the opposite traits (pprr).
Step 4: Use a Punnett square to visualize the combinations of alleles from both parents. This will help you see all possible combinations of traits in the offspring.
Step 5: Count the different phenotypes (observable traits) that result from the combinations. You will find 9 combinations for one phenotype, 3 for another, 3 for a third, and 1 for the last.
Step 6: Write down the expected phenotypic ratio, which is 9:3:3:1.
