Final answer:
In Mendel's experiments with pea plants, all F1 generation plants had violet flowers because violet is a dominant trait over white, which is recessive. The F1 generation was heterozygous, carrying both violet and white alleles. The F2 generation's reappearance of the white flowers in a 3:1 ratio confirmed the pattern of Mendelian inheritance.
Step-by-step explanation:
Understanding Mendelian Inheritance
In the study of Mendelian genetics, we often examine the inheritance pattern of specific traits from one generation to the next. One of the most classic examples is Mendel's experiment with pea plants, where he observed the inheritance of flower color.
The parent generation, known as the P generation, consisted of plants that were true-breeding for certain traits - in this case, pea pod color. Crossed were plants true-breeding for violet flowers with those true-breeding for white flowers.
All offspring in the F1 (filial 1) generation exhibited violet flowers, which indicated that the violet flower color was a dominant trait over the white color, which was recessive. Since no F1 generation plants had white flowers, we infer that the white-flower trait did not simply disappear but was masked by the dominant violet color trait in the F1 generation.
In the F2 generation, when the F1 individuals were crossed, the recessive white-flower trait reappeared in roughly one-quarter of the offspring. This aligns with the expected 3:1 phenotypic ratio predicted by Mendelian inheritance, illustrating that while the F1 generation appeared uniform, they were actually heterozygous for the flower color gene.
The purple flower color, being dominant, manifested in all F1 offspring when they inherited just one allele for it from the P generation. The F2 generation phenotypic ratio of violet to white flowers can be predicted using a Punnett square, which demonstrates how the alleles from each parent can combine in various ways to create the observed 3:1 ratio in their offspring.