The genome of an organism is the whole of its hereditary information encoded in its DNA (or, for some viruses, RNA). This includes both the genes and the non-coding sequences of the DNA. The term was coined in 1920.
Winkler's definition, in translation, runs:
- "I propose the expression genome for the haploid chromosome set, which, together with the pertinent protoplasm, specifies the material foundations of the species ...." p165
However, no single haploid chromosome set defines even the DNA of a species, because of the huge variety of alleles carried by a population. Even a diploid individual carries genetic variety. For that reason Dobzhansky preferred "set of chromosomes", and the definition now must be broader than Winklers' definition. The genome of a haploid chromosome set is merely a sample of the total genetic variety of a species.
The term 'genome' can be applied specifically to mean the complete set of nuclear DNA (the 'nuclear genome') but can also be used of organelles that contain their own DNA, as with the mitochondrial genome or the chloroplast genome.
|Organism||Genome size (base pairs)||Note|
|Virus, Bacteriophage MS2||3569||First sequenced RNA-genome|
|Virus, Phage Φ-X174||5386||First sequenced DNA-genome|
|Virus, Phage λ||5×104|
|Bacterium, Candidatus Carsonella ruddii||1.6×105||Smallest non-viral genome, Feb 2007|
|Bacterium, Escherichia coli||4×106||Best-researched bacterium.|
|Bacterium, Solibactoer usitatus||1×107||Largest known bacterial genome|
|Protist, Amoeba dubia||6.7×1011||Largest known genome, but disputed.|
|Plant, Arabidopsis thaliana||1.57×108||First plant genome sequenced, Dec 2000.|
|Plant, Genlisea margaretae||6.34×107||Smallest recorded flowering plant genome, 2006.|
|Plant, Fritillaria assyrica||1.3×1011|
|Plant, Populus trichocarpa||4.8×108||First tree genome, Sept 2006|
|Yeast, Saccharomyces cerevisiae||2×107|
|Fungus, Aspergillus nidulans||3×107|
|Nematode, Caenorhabditis elegans||9.8×107||First multicellular animal genome, December 1998.|
|Insect, Drosophila melanogaster aka fruit fly||1.3×108|
|Insect, Bombyx mori aka silk moth||5.30×108|
|Insect, Apis mellifera aka honey bee||1.77×109|
|Fish, Tetraodon nigroviridis, type of Puffer fish||3.85×108||Smallest vertebrate genome known|
|Mammal, Homo sapiens||3×109|
|Fish, Protopterus aethiopicus aka marbled lungfish||1.3×1011||Largest vertebrate genome known|
Note: The DNA from a single human cell has a length of ~1.8 m (but at a width of ~2.4 nanometers).
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