The diagram represents one pair of homologous chromosomes during meiosis - HSC - SSCE Biology - Question 10 - 2001 - Paper 1

To determine the genotypes produced from crossing-over during meiosis, we first need to identify the alleles present on each chromosome.

1. 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

2. During crossing-over, segments of these chromatids exchange, resulting in the following combinations:

   • Parental types: ABG and abg
   • Recombinant types: AbG and abG

3. The resulting genotypes after random segregation include:

   • ABG
   • AbG
   • abG
   • abg

4. Therefore, the possible combinations of genotypes produced are:

   • ABG
   • abG
   • Abg
   • abg

The correct answer is (B) ABG, abG, Abg, abg.