Question

Use a Punnett square to deter-

mine the possible genotypes of
the offspring of a BB X Bb cross.
a. all BB
c. BB, Bb, bb
b. BB, Bb
d. all bb

Answer 1

Using a Punnett square for a BB X Bb cross, we find that the possible genotypes of the offspring are 50% homozygous dominant (BB) and 50% heterozygous (Bb), with no homozygous recessive (bb) individuals in the outcome. The correct option is b. BB, Bb.

Step-by-step explanation:

To determine the possible genotypes of the offspring resulting from a BB X Bb cross using a Punnett square, we follow these steps:

1. Place the alleles from the homozygous parent (BB) along one side of the grid.
2. Arrange the alleles from the heterozygous parent (Bb) along the other side of the grid.
3. Fill in the Punnett square by combining the alleles from each parent in each of the squares.

The resulting genotypes in each of the squares will represent the potential genotypes of the offspring:

• BB (from BB and B)
• BB (from BB and B)
• Bb (from BB and b)
• Bb (from BB and b)

Thus, the possible offspring genotypes are all BB and Bb. This gives us the expected ratios of genotypes which are 50% homozygous dominant (BB) and 50% heterozygous (Bb).