To determine the predicted percentage of homozygous black-furred guinea pigs from a cross between a homozygous (BB) guinea pig and a heterozygous (Bb) guinea pig, we can use a Punnett square.
The genotypes we have for the two parent guinea pigs are:
- Parent 1: BB (homozygous)
- Parent 2: Bb (heterozygous)
The possible gametes from each parent are:
- Parent 1 (BB): B, B
- Parent 2 (Bb): B, b
Now we can set up the Punnett square:
B | B
---------------------
B | BB | BB
---------------------
b | Bb | Bb
From this Punnett square, we see the following genotypes among the offspring:
- 2 BB (homozygous black fur)
- 2 Bb (heterozygous black fur)
To find the percentage of homozygous black-furred guinea pigs (BB), we total the number of homozygous individuals and divide by the total number of offspring:
Total offspring = 2 (BB) + 2 (Bb) = 4
Percentage of homozygous black-furred guinea pigs (BB) = (Number of BB / Total offspring) × 100 = (2 / 4) × 100 = 50%
Therefore, the answer is:
50%