Dominant Alleles

A dominant allele is a version of a gene that determines a trait's appearance even if only one copy is present in an individual’s DNA. For example, if you inherit a dominant allele for brown eyes from one parent, you will have brown eyes, regardless of the other parent’s gene. Dominant alleles "show" their trait in the organism's physical features, while recessive alleles require two copies to influence the trait. This means a single dominant allele can mask the effect of a recessive allele when both are present.