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The diagram represents one pair of homologous chromosomes during meiosis - HSC - SSCE Biology - Question 10 - 2001 - Paper 1
Question 10
The diagram represents one pair of homologous chromosomes during meiosis. Crossing-over occurs and random segregation takes place. What genotypes are produced? (A)... show full transcript
Worked Solution & Example Answer:The diagram represents one pair of homologous chromosomes during meiosis - HSC - SSCE Biology - Question 10 - 2001 - Paper 1
Step 1
What genotypes are produced?
Answer
To determine the genotypes produced from crossing-over during meiosis, we first need to identify the alleles present on each chromosome.
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The two homologous chromosomes carry the following allele combinations:
- One chromosome has alleles: A, B, G
- The other homologous chromosome has alleles: a, b, g
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During crossing-over, segments of these chromatids exchange, resulting in the following combinations:
- Parental types: ABG and abg
- Recombinant types: AbG and abG
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The resulting genotypes after random segregation include:
- ABG
- AbG
- abG
- abg
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Therefore, the possible combinations of genotypes produced are:
- ABG
- abG
- Abg
- abg
The correct answer is (B) ABG, abG, Abg, abg.