Question
In Andalusian chickens, black individuals (BB) and white individuals (bb) are homozygous. W black bird is crossed with a white bird, it results in offspring that are blue. If two F1 generation chickens are crossed, what is the probability of each phenotype in the F2 generation, expressed as a ratio? A. 1 Black: 1 White : 2 Blue B. 3 Black: 1 White : 0 Blue C. 3 Black: 0 White : 1 Blue D. 2 Black: 1 White : 1 Blue
Answer
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Cecilia
Professional · Tutor for 6 years
Answer
The correct answer is A. 1 Black : 1 White : 2 Blue.
Explanation
## Step 1In the case of Andalusian chickens, the black and white phenotypes are homozygous, represented by "BB" and "bb" respectively. The heterozygous phenotype, which is blue, is represented by "Bb".## Step 2When two F1 generation chickens (blue, heterozygous) are crossed, the possible combinations of alleles that can be produced are:1. BB (black)2. Bb (blue)3. bB (blue)4. bb (white)## Step 3The combinations BB, Bb, bB, and bb represent the phenotypes black, blue, blue, and white respectively.## Step 4The combinations Bb and bB are identical and represent the blue phenotype. Therefore, they contribute equally to the number of blue chickens in the F2 generation.## Step 5Based on the above analysis, the ratio of the different phenotypes in the F2 generation would be 1 Black : 2 Blue : 1 White.