How many different trait ratios typically occur in the F2 generation?

• A. 1
• B. 2
• C. 3
• D. 4

Answer: (C)

In the context of Mendelian genetics, particularly when considering a monohybrid cross where one trait is examined, the F2 generation typically exhibits a phenotypic ratio of 3:1. This ratio results from the segregation of alleles and represents the phenotypic expression of the dominant and recessive traits.

To break it down, in the P generation (the parental generation), two homozygous individuals are crossed: one for the dominant trait (homozygous dominant) and one for the recessive trait (homozygous recessive). In the F1 generation, all offspring exhibit the dominant phenotype because they inherit one allele from each parent. When these F1 individuals are crossed to produce the F2 generation, the segregation of alleles during gamete formation leads to three individuals showing the dominant trait and one showing the recessive trait in the resultant offspring. Therefore, the F2 generation will display three different phenotypes for the dominant trait compared to one phenotype for the recessive trait, resulting in a typical ratio of 3:1.

This foundational principle of inheritance explains why there are three observable outcomes related to the dominant trait in the F2 generation, guiding the understanding of genetic trait ratios in subsequent crosses and providing