Question

In peas, the allele for green pods is dominant over the allele for yellow pods. Also, the allele for tall stem length is dominant over that for short stem length. These genes are unlinked. A pure breeding tall pea plant with green pods is crossed with a short pea plant with yellow pods. Write the genotypes of the pea plants and their gametes in the P, F1, and F2 generations. Draw the chromosomes. Use a Punnett square to figure out the phenotypic ratios (the proportion of pea plants with a given phenotype) in the F2 generation.

Answer 1

Answer:

Gametes of the parents are AB for one parent and ab for the other

Gametes of the F1: AB Ab aB ab

Phenotypic ratio in the F2 generatio is 9:3:3:1

Explanation:

If we name the gene for pods color with A and gene for length of the stem with B, then, a pure breeding tall pea plant with green pods which is crossed with a short pea plant with yellow pods is:

P: AABB  x  aabb

F1: AaBb

F2: picture

Gametes of the parents are AB for one parent and ab for the other

Gametes of the F1: AB Ab aB ab

Phenotypic ratio in the F2 generatio is 9:3:3:1

9-the same phenotype as parents (AABB, AABb, AaBB, AaBb genotypes)

3-tall plant with yellow pods (aaBB, aaBb genotypes)

3-short plant with green pods (AAbb, Aabb genotypes)

1-short plant with yellow pods (aabb genotype)