The Difference Between Partially Dominant and Fully Dominant Genotypes

Explaining Partially Dominant and Fully Dominant Genotypes

Partially dominant genotype: In partial dominance, the heterozygote phenotype showcases an intermediate trait between the two homozygous phenotypes. This phenomenon is also known as incomplete dominance, where neither allele is completely dominant over the other.

An example of this can be seen in snapdragons with flower color. When a red-flowered plant (CRCR) is crossed with a white-flowered plant (CWCW), the offspring will have pink flowers (CRCW). This pink color is the intermediate phenotype between red and white, displaying characteristics of both homozygous phenotypes.

Fully dominant genotype: On the other hand, in complete dominance, the heterozygote phenotype is identical to the homozygous dominant phenotype. One allele in the genotype completely masks the expression of the other allele.

For instance, if we consider the trait of plant height in pea plants, where tall (T) is dominant over short (t), a pea plant with genotype Tt (heterozygous) will still exhibit the tall phenotype. This is the same phenotype as a pea plant with genotype TT (homozygous dominant), showcasing complete dominance.

In summary, partially dominant genotypes display an intermediate phenotype between the homozygous genotypes, while fully dominant genotypes resemble one of the homozygous genotypes, masking the expression of the other allele completely.