Answer:
Mendel used the dihybrid cross between a homozygous pea plant with yellow round seeds and a homozygous pea plant with green wrinkled seeds. The parents have the alleles YYRR and yyrr, respectively.
During meiosis, the chromosomes are separated so that only half the genes are transported to the gametes. The possible genotypes of the gametes then become YR and yr.
As the parents are crossed, the fusion of the gametes results in the F1 hybrid with the YyRr genotype.
Explanation:
The F1 hybrids have the phenotype of yellow round seeds as the dominant allele Y for yellow color, and the dominant allele R for the roundness is expressed.
The alleles in F1 hybrids can now be segregated into four parts; Y for yellow color, y for green color, R for roundness, and r for wrinkledness.
The four alleles can combine in several combinations to produce different genotypes and phenotypes.
On further crossing, four types of gametes can be formed; YR, Yr, yR, and yr. These gametes fuse to form sixteen individuals in the F2 generation.
The ratio of the F2 hybrids is 9 yellow round: 3 yellow wrinkled: 3 green round: 1 green wrinkled.
This proves that both characters are inherited independently of one another and are expressed according to their dominance.
