In four o'clock plants, many flower colors are observed. In a cross involving two true-breeding strains, one crimson and the other white, all of the F₁ generation were rose color. In the F₂, four new phenotypes appeared along with the P₁ and F₁ parental colors. The following ratio was obtained: 1/16 crimson 4/16 rose 2/16 orange 2/16 pale yellow 1/16 yellow 4/16 white 2/16 magenta Propose an explanation for the inheritance of these flower colors.

Key Concepts

Mendelian Inheritance

Mendelian inheritance refers to the principles of heredity established by Gregor Mendel, which include the concepts of dominant and recessive traits. In this case, the crimson and white flower colors represent two alleles, where one may be dominant over the other. The F₁ generation displaying a rose color suggests incomplete dominance, where neither allele is completely dominant, resulting in a blend of traits.

Phenotypic Ratios

Phenotypic ratios describe the relative frequencies of different phenotypes in the offspring of a genetic cross. The observed 1:4:2:2:1:4:2 ratio in the F₂ generation indicates a complex inheritance pattern, likely involving multiple alleles and possibly epistasis, where one gene affects the expression of another. Understanding these ratios helps in predicting the distribution of traits in future generations.

Multiple Alleles and Incomplete Dominance

Multiple alleles refer to the presence of more than two alleles for a genetic trait within a population. In the case of the four o'clock plants, the variety of flower colors suggests that multiple alleles are influencing the phenotype. Incomplete dominance occurs when the heterozygous phenotype is a blend of the two homozygous phenotypes, as seen with the rose color in the F₁ generation, leading to a diverse range of colors in the F₂ generation.