Two true-breeding pea plants were crossed. one parent is round, terminal, violet, constricted, while the other expresses the respective contrasting phenotypes of wrinkled, axial, white, full. the four pairs of contrasting traits are controlled by four genes, each located on a separate chromosome. in the f1 only round, axial, violet, and full were expressed. in the f2, all possible combinations of these traits were expressed in ratios consistent with mendelian inheritance. (a) what conclusion about the inheritance of the traits can be drawn based on the f1 results? (b) in the f2 results, which phenotype appeared most frequently? what mathematical expression predicts the probability of occurrence of this phenotype? (c) which f2 phenotype is expected to occur least frequently? what mathematical expression predicts this probability? (d) in the f2 generation, how often is either of the p1 phenotypes likely to occur? express your answer as a fraction (example: 3/16).

9/256

Explanation:

Parental generation: two true-breeding plants (homozygous for all genes).

Round, terminal, violet, constricted X wrinkled, axial, white, full

F1: Homogeneous round, axial, violet, and full

According to Mendel's Law of Dominance, the traits observed in the phenotype of F1 are dominant.

Therefore, the genotypes of the parents are:

The phenotypes of the P1 individuals that we're looking for in the F2 as a result of crossing F1xF1 are:

The genes are independent, so we can use Mendel's laws individually to predict the expected phenotypes for each gene, and then multiply all the probabilities to obtain the probability of having the P1 phenotypes.

Probability of R_aaV_ff  = 3/4 × 1/4 × 3/4 × 1/4 = 9/256

Probability of rrA_vvF_  = 1/4 × 3/4 × 1/4 × 3/4 = 9/256

Two true-breeding pea plants were crossed. One parent is round, terminal, violet, constricted, while the other expresses the respective contrasting phenotypes of wrinkled, axial, white, full. The four pairs of contrasting traits are controlled by four genes, each located on a separate chromosome. In the F1 only round, axial, violet, and full were expressed. In the F2, all possible combinations of these traits were expressed in ratios consistent with Mendelian inheritance