Describe the traits that make Pisum sativum an ideal organism for genetic studies. Why did Mendel ultimately decide not to include exterior seed coat color (gray vs. white) as one of the traits he analyzed?

Question

What will be an ideal response?

Answer 1

There are many varieties of peas with distinct, heritable features in the form of dichotomous phenotypes that can be easily observed and quantified. In addition, mating of plants can be closely controlled. Since each pea plant has both sperm-producing (stamens) and egg-producing (carpels) organs, they can be self-crossed to generate true-breeding plants. After creating these true-breeding plants, Mendel could test for dominant or recessive inheritance patterns by cross-pollination (fertilization between different plants). Mendel initially selected an eighth trait producing either gray or white exterior seed coats. Early in his analysis, he saw that plants with purple flowers always had gray seed coats and that those with white flowers always had white seed coats. He speculated that flower color and seed-coat color were determined by the same genetic mechanism, and he was correct. (The pigment anthocyanin is produced by plants that have purple flower color and gray seed coats, but a mutation eliminates anthocyanin production in plants with white flowers and white seed coats.)