. . . . . . . . "MSH: Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.,CSP: one of a series of possible alternative forms of a given gene, differing in DNA sequence, and affecting the functioning of a single product.,NCI: One of two or more DNA sequences occurring at a particular gene locus. Typically one allele (normal DNA sequence) is common, and other alleles (mutations) are rare.,NCI: Mutually exclusive alternative forms of the same gene occupying the same locus on homologous chromosomes, differing in DNA sequence and governing the same biochemical and developmental process." . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .