In a population of rabbits, black fur (B) is dominant over white fur (b). If two heterozygous black rabbits (Bb) are mated, what is the expected phenotypic ratio of their offspring?
Practice Questions
1 question
Q1
In a population of rabbits, black fur (B) is dominant over white fur (b). If two heterozygous black rabbits (Bb) are mated, what is the expected phenotypic ratio of their offspring?
1:1
3:1
2:1
1:2:1
The cross Bb x Bb results in 1 BB (black), 2 Bb (black), and 1 bb (white), giving a phenotypic ratio of 3:1.
Questions & Step-by-step Solutions
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Q
Q: In a population of rabbits, black fur (B) is dominant over white fur (b). If two heterozygous black rabbits (Bb) are mated, what is the expected phenotypic ratio of their offspring?
Solution: The cross Bb x Bb results in 1 BB (black), 2 Bb (black), and 1 bb (white), giving a phenotypic ratio of 3:1.
Steps: 6
Step 1: Identify the genotypes of the parent rabbits. Both are heterozygous black rabbits, which means their genotypes are Bb.
Step 2: Set up a Punnett square to visualize the possible combinations of alleles from the parents. The rows and columns will represent the alleles from each parent.
Step 3: Fill in the Punnett square. The combinations will be: BB, Bb, Bb, and bb.
Step 4: Count the different genotypes from the Punnett square. You will have 1 BB, 2 Bb, and 1 bb.
Step 5: Determine the phenotypes based on the genotypes. BB and Bb both result in black fur, while bb results in white fur.
Step 6: Calculate the phenotypic ratio. You have 3 black rabbits (1 BB + 2 Bb) and 1 white rabbit (1 bb), giving a ratio of 3 black to 1 white.
