In pea plants, plant height, seed shape, and seed color are governed by three independently assorting genes. The three genes have dominant and recessive alleles, with tall (T) dominant to short (t), round (R) dominant to wrinkled (r), and yellow (G) dominant to green (g).

If a true-breeding tall, wrinkled, yellow plant is crossed to a true-breeding short, round, green plant, what phenotypic ratios are expected in the F₁ and F₂?

Key Concepts

Mendelian Genetics

Mendelian genetics is the study of how traits are inherited through generations based on the principles established by Gregor Mendel. It includes concepts such as dominant and recessive alleles, which determine the phenotype of an organism. In this case, the traits of plant height, seed shape, and seed color are governed by specific alleles that follow Mendel's laws of inheritance.

Independent Assortment

The principle of independent assortment states that alleles for different traits segregate independently of one another during gamete formation. This means that the inheritance of one trait does not affect the inheritance of another. In the context of the question, the genes for plant height, seed shape, and seed color assort independently, allowing for a variety of combinations in the offspring.

Phenotypic Ratios

Phenotypic ratios refer to the relative frequencies of different phenotypes in the offspring resulting from a genetic cross. In this scenario, the expected phenotypic ratios in the F₁ and F₂ generations can be calculated using a Punnett square, which visually represents the combinations of alleles from the parents. Understanding these ratios is crucial for predicting the traits of the offspring based on the parental genotypes.