Allele

Mutually exclusive forms of the same gene, occupying the same locus on homologous chromosomes, and governing the same biochemical and developmental process.

Any of a number of codings for a gene; different versions of a gene.

Any one of a series of different genes that may occupy the same location (locus) on a specific chromosome.

One of two or more alternative forms of a hereditary unit (gene) situated in the same site on paired (homologous) chromosomes and determining a given characteristic of an organism. For example, the gene for blue eye color and the gene for brown eye color are two alleles of the gene for eye color. Also called allelomorph.

An allele, or allelomorph, is a gene which may exist in one or more forms, only one of which can occur in a given chromosome. Two alleles of a given gene are at the same relative positions on a pair of homologous (similarly structured) chromosomes. If the two alleles are identical, the subject is homozygous for the gene — namely, the genes will exert a unanimous influence on a particular characteristic. If the alleles are different, with one having a dominant and the other a recessive influence, the subject is heterozygous.

One of two or more different genes containing specific inheritable characteristics that occupy corresponding positions (loci) on paired chromosomes. A pair of alleles is usually indicated by a capital letter for the dominant and a lowercase letter for the recessive. An individual with a pair of identical alleles, either dominant or recessive, is said to be homozygous for this gene. The union of a dominant gene and its recessive allele produces a heterozygous individual for that characteristic. Some traits may have multiple alleles (i.e., more than two possibilities), but an individual has only two of those alleles (e.g., the genes for blood type, A, B, and O, are at the same position on the chromosome pair, but an individual has only two of these genes, which may be the same or different).

In the intricate landscape of chromosomal arrangements, a notable phenomenon arises wherein distinct genetic entities, known as genes, find themselves occupying a shared abode within a specific locus on a chromosome.