An allele is an alternative form of a gene that is located at a specific position on a specific chromosome. Mendel's law of segregation formulates the process by which an allele is transmitted.
These DNA codings help determine specific traits that can be passed on from parents to offspring and traits that the parents may have had that will remain dormant in their offspring. Organisms have two alleles for each trait. When the alleles of a pair are heterozygous, one is dominant and the other is recessive. The dominant allele is expressed and the recessive allele is masked. For example, in humans the allele for brown eyes is dominant, and the allele for blue eyes is recessive.