Two pure bred strains of peas are crossed: wrinkled, yellow x round, green. All the offspring are round, yellow. These offspring were self-crossed and their progeny produced four different phenotypes. For this question assume the random assortment of two unlinked genes. See diagram below.

Question

Two pure bred strains of peas are crossed: wrinkled, yellow x round, green. All the offspring are round, yellow. These offspring were self-crossed and their progeny produced four different phenotypes. For this question assume the random assortment of two unlinked genes. See diagram below.

Using A and a to designate pea shape, and B and b to designate pea colour, assign genotypes to each phenotype in the P1 and F1 generations. Hint: the phenotypic ratios should allow you to determine the dominant phenotypes.

Genotype of wrinkled yellow parent:?

Genotype of round green parent:?

Genotype of F1: ?

Answer 1

To determine the genotypes of the parents and the F1 generation, we need to understand the principles of Mendelian genetics and use the given information.

Mendelian genetics describe how traits are inherited from parents to offspring. In this case, we are considering two traits: pea shape (wrinkled or round) and pea color (yellow or green).

Let's analyze the given information step by step:

Step 1: Identify the phenotypes of the parents.
The parental generation consists of two purebred strains: wrinkled, yellow (wrinkled, yellow) and round, green (round, green) peas. So, the phenotypes of the parents are:

Wrinkled yellow parent: Wrinkled, yellow
Round green parent: Round, green

Step 2: Assign the genotypes to the parents.
Since the parents are purebred strains, we know that they are homozygous for each trait. Let's assign the genotypes using A and a for pea shape and B and b for pea color:

Wrinkled yellow parent: aaBB
Round green parent: AAbb

Step 3: Determine the genotypes of the F1 generation.
When the purebred parents are crossed, their alleles combine randomly in the offspring. In this case, all the offspring are round and yellow (round, yellow).

By analyzing the phenotypic ratios, we can determine that round and yellow are the dominant phenotypes. This suggests that the dominant traits come from the parents, making them homozygous dominant for both traits. Therefore, the genotypes of the F1 generation plants are:

Genotype of F1: AaBb

To recap:

Genotype of wrinkled yellow parent: aaBB
Genotype of round green parent: AAbb
Genotype of F1: AaBb