A trisomic of the genotype can produce a gamete of genotype a. The meiotic products of trisomic with genotype are as follows:
Here, three equally likely segregations would have taken place. Thus, the three gametes formed would be as follows:
• A
• Aa
• AA
The probability of the gametes would be as follows:
• The genotype would be
• The genotype would be
• The genotype would be
• The genotype would be
Hence, the occurrence of a gamete with the genotype would be of the total number of gametes.