Definition of Genome

Genome: All of the genetic information, the entire genetic complement, all of the hereditary material possessed by an organism.

Humans and many other higher animals actually have two genomes, which together make up the total genome:

1. A chromosomal genome -- inside the nucleus of the cell in the familiar form of chromosomes; and
2. A mitochondrial genome -- outside the nucleus in the cytoplasm of the cell, usually in the form of one round chromosome (the mitochondrial chromosome).

The historical tendency has been to focus on the human genome somewhat to the exclusion of the genomes of other organisms. This anthropomorphic view of genomics is perhaps understandable but is a narrow view of the world. There are many other genomes including, for example, the:

• Arabidopsis thaliana genome (mustard weed)
• C. elegans genome (a roundworm)
• Drosophila genome (the fruitfly)
• H. flu genome (a bacterium)
• Mouse genome
• Rice genome
• Vibrio cholerae genome (cholera bacteria)
• Yeast genome

The word genome dates to 1930. It was cobbled from the German Gen, gene + -om (from the Greek soma, body). In the 1990s genome went from being a highly specialized term not even in much usage in genetics to a word that is now in common general currency. As with all revolutions, the Genetics Revolution has ushered in a revolution in words.

Source: MedTerms™ Medical Dictionary
http://www.medterms.com/script/main/art.asp?articlekey=3580
Last Editorial Review: 2/4/2004