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Noun, pl. genes

1. The biologic unit of heredity, self-reproducing and located at a definite position (locus) on a particular chromosome. (Dorland’s Medical Dictionary for Health Consumers. © 2007 by Saunders)

2. A hereditary unit that occupies a specific location on a chromosome, determines a particular characteristic in an organism by directing the formation of a specific protein, and is capable of replicating itself at each cell division. (The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company)

3. A building block of inheritance, which contains the instructions for the production of a particular protein, and is made up of a molecular sequence found on a section of DNA. Each gene is found on a precise location on a chromosome. (Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.)

4. The biologic unit of inheritance, consisting of a particular nucleotide sequence within a DNA molecule that occupies a precise locus on a chromosome and codes for a specific polypeptide chain. In diploid organisms, which include humans and other mammals, genes occur as paired alleles. Kinds of genes include complementary genes, mutant genes, operator genes, pleiotropic genes, regulator genes, structural genes, and supplementary genes. See also chromosome, cistron, deoxyribonucleic acid, operon. (Mosby’s Medical Dictionary, 8th edition. © 2009, Elsevier.)


Word origin: From Greek, genein, to produce

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