The most common example of a recessive gene is eye color. Brown eyes are dominant, while gray, green, hazel and blue eyes occur due to recessive genes.
Dominant and recessive genes describe the ability of sexually reproducing organisms to have two alleles for one gene. Humans are sexually reproducing organisms that give their children two copies of each gene. The two copies are known as the dominant and recessive copy, and each one needs a different environment to be expressed. For example, a dominant brown eye gene copy will give a child brown eyes if present with only one copy. However, recessive genes need two copies in order to be expressed. For instance, people with green eyes must have been given two recessive gene copies for green eyes.