allele /əlēl″/ , 1. one of two or more alternative forms of a gene that occupy corresponding loci on homologous chromosomes. Each allele encodes a phenotypic feature or a certain inherited characteristic. An individual normally has two alleles for each gene, one contributed by the mother and one by the father. If both alleles are the same, the individual is homozygous; if the alleles are different, the individual is heterozygous. In heterozygous individuals, one of the alleles is usually dominant, and the other is recessive. In humans, for example, the allele for brown eyes is dominant, and the allele for blue eyes is recessive. 2. one of two or more contrasting characteristics transmitted by alternative forms of a gene. Also called allelomorph. −allelic, adj.
