How does a heterozygous pea plant produce gametes with different alleles?

A heterozygous pea plant, which possesses two different alleles for a specific trait (such as Rr for flower color), produces gametes with different alleles through the process of meiosis.1

This mechanism is the physical basis for Gregor Mendel’s law of segregation. During meiosis, the homologous chromosomes—each carrying one of the two different alleles—pair up and then separate, moving to opposite poles of the cell. As a result, the diploid cell divides to form haploid gametes, ensuring that each gamete receives only one of the two alleles.231

Consequently, a heterozygote produces equal numbers of gametes containing the dominant allele and gametes containing the recessive allele. This separation ensures that the alleles do not blend, allowing them to remain distinct and be passed on to the next generation in predictable ratios.13