To determine the percentage of offspring that will have brown eyes from a cross between a heterozygous brown-eyed individual (Bb) and a homozygous blue-eyed individual (bb), we can use a simple Punnett square.
- The alleles from the brown-eyed parent (Bb) can be either B or b.
- The alleles from the blue-eyed parent (bb) can only be b.
The possible combinations from the Punnett square will be:
- Bb (brown eyes)
- bb (blue eyes)
- Bb (brown eyes)
- bb (blue eyes)
Here are the offspring combinations:
- Bb (brown eyes)
- bb (blue eyes)
This gives us:
- 2 Bb (brown-eyed)
- 2 bb (blue-eyed)
Thus, the genotypic ratio is 2 Bb : 2 bb, or simplified, 1:1.
In percentage terms, half of the offspring (1 out of 2) will have brown eyes:
- Brown-eyed offspring: 50%
- Blue-eyed offspring: 50%
Therefore, the answer is 50% of the offspring will have brown eyes.
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