What ratio of traits is typically observed in the offspring of the F2 generation?

• A. 1:1
• B. 2:1
• C. 3:1
• D. 4:1

Answer: (C)

In the context of Mendelian genetics, the typical ratio of traits observed in the offspring of the F2 generation, particularly in a monohybrid cross, is 3:1. This ratio arises from the segregation of alleles during the formation of gametes in the F1 generation, which are heterozygous for a particular trait.

When two heterozygous individuals (for example, Aa x Aa) are crossed, the possible gametes produced are A and a. The combinations of these gametes in the offspring lead to the following genotype ratios: 1 AA (homozygous dominant), 2 Aa (heterozygous), and 1 aa (homozygous recessive). These genotypes correspond to phenotypes where the dominant trait is expressed in both the homozygous dominant (AA) and heterozygous (Aa) individuals, while the recessive trait is expressed only in the homozygous recessive (aa) individuals.

Thus, when these are counted in terms of phenotype, the distribution reflects one homozygous dominant and two heterozygous individuals exhibiting the dominant trait, while one individual shows the recessive trait. This results in a classic 3:1 phenotypic ratio