What is the typical phenotypic ratio found in the final generation of Mendelian monohybrid crosses?

In Mendelian genetics, a monohybrid cross involves examining the inheritance of a single trait controlled by one gene with two alleles. When two heterozygous parents (both carrying one dominant and one recessive allele, such as Aa x Aa) are crossed, the resulting offspring exhibit a typical phenotypic ratio of 3:1. This ratio emerges because:

1. The dominant allele (A) masks the presence of the recessive allele (a).
2. In this cross, the potential genetic combinations for the offspring include: AA (homozygous dominant), Aa (heterozygous), and aa (homozygous recessive).
3. Out of these combinations, three display the dominant phenotype (AA and Aa) while one exhibits the recessive phenotype (aa), leading to a final ratio of 3 displaying the dominant trait for every 1 displaying the recessive trait.

Therefore, in a typical monohybrid cross, the standard outcome reflects this 3:1 phenotypic ratio for the final generation.