 If the father has two copies of an allele for red hair, and the mother has two copies for brown hair, all their children get the two alleles that give different instructions, one for red hair and one for brown.The hair color of these children depends on how these alleles work together.If one allele dominates the instructions from another, it is called the "dominant" allele, and the allele that is overridden is called the "recessive" allele.