the smallest transmissible unit of genetic material (basic unit of heredity) consistently associated with a single primary genetic effect —note genes are ultramicroscopic and act as if linearly arranged at fixed places (loci) on a chromosome transmitted in the gametes from parent to offspring, governing the transmission and development of a hereditary character —see allele, character, cytoplasm, genotype, germplasm, locus, mutation This definition last updated 10/24/2008