In a certain species, the allele for blue eyes (b) is recessive to the allele for brown eyes (B). If two heterozygous brown-eyed individuals (Bb) have children, what is the probability that a child will have blue eyes?
Practice Questions
1 question
Q1
In a certain species, the allele for blue eyes (b) is recessive to the allele for brown eyes (B). If two heterozygous brown-eyed individuals (Bb) have children, what is the probability that a child will have blue eyes?
0%
25%
50%
75%
The cross Bb x Bb results in a 1/4 chance of bb (blue eyes), so the probability is 25%.
Questions & Step-by-step Solutions
1 item
Q
Q: In a certain species, the allele for blue eyes (b) is recessive to the allele for brown eyes (B). If two heterozygous brown-eyed individuals (Bb) have children, what is the probability that a child will have blue eyes?
Solution: The cross Bb x Bb results in a 1/4 chance of bb (blue eyes), so the probability is 25%.
Steps: 7
Step 1: Understand the alleles. The allele for blue eyes is 'b' and is recessive, while the allele for brown eyes is 'B' and is dominant.
Step 2: Identify the parents' genotypes. Both parents are heterozygous brown-eyed, which means their genotypes are 'Bb'.
Step 3: Set up the Punnett square. Create a 2x2 grid to show the possible combinations of alleles from the parents.
Step 4: Fill in the Punnett square. The combinations will be: BB, Bb, Bb, and bb.
Step 5: Count the outcomes. There is 1 'bb' (blue eyes), 2 'Bb' (brown eyes), and 1 'BB' (brown eyes).
Step 6: Calculate the probability. Out of 4 total combinations, 1 results in blue eyes (bb).
Step 7: Convert the count to a probability. The probability of having blue eyes is 1 out of 4, which is 25%.
