A recessive gene is a type of gene that only expresses its traits when two copies are present, one inherited from each parent. If an individual has one dominant gene and one recessive gene for a particular trait, the dominant gene will mask the effect of the recessive one. This means that the trait associated with the recessive gene will not be visible in the individual's appearance. For example, in the case of eye color, the gene for brown eyes is dominant, while the gene for blue eyes is recessive. A person with one brown eye gene and one blue eye gene will have brown eyes, as the dominant gene takes precedence. Only individuals with two blue eye genes will have blue eyes, showcasing the recessive trait.