Question

In this tutorial you will examine dihybrid crosses: crosses where alleles at separate loci assort independently into gametes at meiosis. You will also use logic to determine unknown genotypes, phenotypes, and genetic ratios from given data.

Part A - Deducing phenotypes and genotypes of selfed parents

Mendel studied pea plants dihybrid for seed shape (round versus wrinkled) and seed color (yellow versus green). Recall that

the round allele (R) is dominant to the wrinkled allele (r) and

the yellow allele (Y) is dominant to the green allele (y).

The table below shows the F₁ progeny that result from selfing four different parent pea plants.

Use the phenotypes of the F₁ progeny to deduce the genotype and phenotype of each parent plant.

Complete the table by dragging the correct label to the appropriate location. Labels can be used once, more than once, or not at all.

Answer 1

Plant 1 Plant 2 Plant 3 Plant 4 Parent phenotypeO Parent genotype Rryy RRYy rVy Fi progeny phenotypes from selfed parent

Parental genotype of plan Parental genotype of plant 2: Rrgg RrGg Rg Rg rg g Parental genotype of plant 4: rrgg Parental genotype of plant 3: RRGg rg rg rg rg