An allele (A) is recessive if the phenotype of the heterozygote (Aa) is the same as the homozygote (aa) for the alternative allele (a) and different from the homozygote for the recessive (AA). The allele (a) controls the heterozygote's phenotype and is called dominant. An allele may be partly, rather than fully, recessive; in that case, the heterozygous phenotype is nearer to, rather than identical with, the homozygote for the dominant allele.