recessive

recessive A genetic trait that appears only in individuals who have received two copies of a mutant gene, one copy from each parent. The individuals with a double dose of the mutated gene are called homozygotes. Their parents, each with a single dose of the mutated gene, appear normal and are called heterozygotes, or gene carriers. There are two types of recessive diseases—autosomal recessive and Xlinked recessive—that describe different patterns of inheritance. The opposite of recessive is dominant. See also autosomal recessive trait; dominant; Xlinked recessive.