In a genetic cross of Bb x Bb, what is the genotypic ratio of the offspring?

In a genetic cross involving two heterozygous individuals for a single trait, represented as Bb x Bb, we can determine the genotypic ratio using a Punnett square. Each parent can pass on either the dominant allele (B) or the recessive allele (b) to their offspring.

When we set up the Punnett square for this cross, the possible combinations of alleles for the offspring are as follows:

1. BB (homozygous dominant)

2. Bb (heterozygous)

3. Bb (heterozygous)

4. bb (homozygous recessive)

Now, counting each type of genotypic combination, we find:

• There is 1 BB,

• 2 Bb,

• 1 bb.

This results in a total of three different types of genotypes: 1 BB, 2 Bb, and 1 bb. Therefore, the genotypic ratio of the offspring is 1:2:1.

The chosen answer accurately reflects the outcome of this parental cross, illustrating how the different combinations of alleles can lead to a specific distribution of genotypes among the offspring.