The illustration below shows a crossing between a black bull (B) and a white cow (W) - NSC Agricultural Sciences - Question 4 - 2023 - Paper 2
Question 4
The illustration below shows a crossing between a black bull (B) and a white cow (W).
P1
BB X WW
Process 1
Gametes
B X W
F1-generation
BW (All grey)
F1
BW X 2
F... show full transcript
Worked Solution & Example Answer:The illustration below shows a crossing between a black bull (B) and a white cow (W) - NSC Agricultural Sciences - Question 4 - 2023 - Paper 2
Step 1
4.1.1 Identify the pattern of inheritance in the diagram above.
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Answer
The pattern of inheritance illustrated in the diagram is known as incomplete dominance. This occurs when the offspring (F1) exhibit a phenotype that is a blend of the parental traits rather than expressing one trait fully.
Step 2
4.1.2 Justify the answer to QUESTION 4.1.1.
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Answer
The justification for identifying the pattern of inheritance as incomplete dominance is based on the observation that the F1 generation shows an intermediate phenotype (BW), which is gray. This indicates that neither the black (B) nor the white (W) allele is completely dominant over the other.
Step 3
4.1.3 Label each of the following represented in the diagram above:
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Answer
(a) Process by 1: Meiosis
(b) Genotype by 2: BW
(c) Phenotype by 3: Black
Step 4
4.1.4 Write down each of the following:
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Answer
(a) Genotypic ratio of the F1-generation: 1 BW
(b) Phenotypic ratio of the F2-generation: 1 black : 2 gray : 1 white
