| − | The '''phenotype''' is the observable traits or characteristics of an [[organism]], for example hair color, weight, or the presence or absence of a [[disease]]. Phenotypic traits are not necessarily [[genetic]]. | + | The '''phenotype''' is the observable traits or characteristics of an [[organism]], for example hair color, weight, or the presence or absence of a [[disease]]. Differences in phenotype are caused by differences in genotype, but not all phenotypes necessarily have the same genotype. Organisms that contain a [[dominant allele]] and a [[recessive allele]] for a trait will have the same phenotype as an organism that has two of the same alleles for the dominant trait. |