The gene-dose effect refers to the relationship is between the number of copies of a particular gene and the extent to which that gene affects a phenotype. An individual who has two copies of a particular gene may exhibit a different phenotype (observable trait) than an individual with only one copy of the same gene. Synonyms for the gene-dose effect may include gene dosage effect, allelic dosage effect, dosing effect, or simply gene effect. It is important for researchers to understand these synonyms in order to properly interpret scientific literature and discussions regarding gene expression and phenotype. This knowledge also helps in developing effective treatments and therapies for genetic diseases.