Answer:
When two mice that are heterozygous for black coat color (Bb) are mated, and coat color in mice is controlled by a single pair of genes, the expected genotypic ratio for coat color in the offspring follows Mendelian genetics principles.
For each parent mouse (Bb), there are two possible gametes (B and b) that can combine during fertilization. This results in the following genotypic ratio for the offspring:
1. Homozygous Black (BB): 1/4 or 25%
2. Heterozygous Black (Bb): 2/4 or 50%
3. Homozygous Brown (bb): 1/4 or 25%
Therefore, the expected genotypic ratio for coat color in the offspring of two heterozygous mice for black coat color is:
- Homozygous Black (BB): 25%
- Heterozygous Black (Bb): 50%
- Homozygous Brown (bb): 25%