Recessive

A property of an allele that means its Phenotype is expressed only if there is no Dominant allele to “take precedence”. An individual has two copies of most genes, so for the recessive allele’s Phenotype to express, both of these genes must be of the Recessive allele (Homozygous Recessive). However, males only have one copy of each gene on the X-Chromosome, so recessive alleles are always expressed.