Incomplete dominance is a genetic phenomenon in which the phenotype of the heterozygous individual is intermediate between those of the homozygous dominant and homozygous recessive individuals. In other words, the expression of both alleles is not completely dominant or recessive, resulting in a blended phenotype.
The two traits that are determined by incomplete dominance are:
1. Flower color in snapdragons: In snapdragons, the allele for red flowers (R) is incompletely dominant over the allele for white flowers (W). Heterozygous individuals (RW) have pink flowers, which is an intermediate phenotype between red and white.
2. Coat color in some animals, such as horses: In some animals, such as horses, the allele for black coat color (B) is incompletely dominant over the allele for white coat color (W). Heterozygous individuals (BW) have a gray coat color, which is an intermediate phenotype between black and white.
In both cases, the expression of both alleles is not completely dominant or recessive, resulting in a blended phenotype that is intermediate between the homozygous dominant and homozygous recessive phenotypes.