How does partial dominance affect allele expression?

Partial dominance describes a situation where one allele does not completely mask the expression of another allele. Instead, one allele exerts a partial influence over the phenotype while the other contributes to the overall trait expression as well. This results in a phenotype that is intermediate between the two homozygous forms.

For example, consider a plant that has one allele for red flowers and another for white flowers. In a case of partial dominance, the resulting flower color in the heterozygous plant might be pink, illustrating how one allele partially masks the effect of the other rather than wholly dominating it or being entirely unexpressed. This concept helps to illustrate the complexity of genetic traits, showing that the interaction of alleles can lead to a spectrum of phenotypic outcomes rather than simple Mendelian traits where one allele completely governs the phenotype.