Incomplete dominance: A phenotype that is a combination of the two alleles; the heterozygous organism can be a blend between the phenotype of its homozygous parents.
Codominance: The expression of both alleles, where neither one is dominant or recessive.
Multiple Alleles: there are more than two forms of an allele at a locus.
Complementary gene: recessive alleles of 2 different genes may give the same phenotype.
Epistasis: a gene modifies the expression of another gene (e.g. inhibition, suppression, etc.)
Polygenic inheritance: A trait that is controlled by multiple genes.
Genetic background and the environment contribute to incomplete penetrance and variable expressivity.
Incomplete penetrance: the phenotypes do not 100% match the genotype.
Variable expressivity: stronger/weaker versions of a phenotype.
