1) One of a number of alternative forms of a gene. Commonly only two alternative forms exist for a gene.
2) Either of a pair (or series) of alternative forms of a gene that can occupy the same locus on a particular chromosome and that control the same character
1 Any of a large variety of proteins normally present in the body or produced in response to an antigen which it neutralizes, thus producing an immune response
1 Reproduction without the fusion of gametes