Genome

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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.[1]

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 ...." [2]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",[3] 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.

Genome sizes[change | change source]

Organism Genome size (base pairs) Note
Virus, Bacteriophage MS2 3569 First sequenced RNA-genome[4]
Virus, SV40 5224[5]
Virus, Phage Φ-X174 5386 First sequenced DNA-genome[6]
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.[7]
Bacterium, Solibactoer usitatus 1×107 Largest known bacterial genome
Protist, Amoeba dubia 6.7×1011 Largest known genome, but disputed.[8]
Plant, Arabidopsis thaliana 1.57×108 First plant genome sequenced, Dec 2000.[9]
Plant, Genlisea margaretae 6.34×107 Smallest recorded flowering plant genome, 2006.[9]
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.[10]
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).

Other pages[change | change source]

References[change | change source]

  1. by Hans Winkler, Professor of Botany at the University of Hamburg, Germany, as a combination of the words gene and chromosome.Joshua Lederberg and Alexa T. McCray (2001). "'Ome Sweet 'Omics -- A genealogical treasury of words". The Scientist 15 (7).
    An online copy is available here: [1]
  2. Winkler H. 1920. Verbreitung und Ursache der Parthenogenesis im Pflanzen- und Tierreiche. Fischer, Jena.
  3. Dobzhansky T. 1937. Genetics and the origin of species. Columbia N.Y.
  4. Fiers W. et al (1976). "Complete nucleotide-sequence of bacteriophage MS2-RNA - primary and secondary structure of replicase gene". Nature 260: 500-507.
  5. Fiers W. et al (1978). "Complete nucleotide sequence of SV40 DNA". Nature 273 (5658): 113-120.
  6. Sanger F. et al (1977). "Nucleotide sequence of bacteriophage phi X174 DNA". Nature 265 (5596): 687-695.
  7. Frederick R. Blattner et al (1997). "The complete genome sequence of Escherichia coli K-12". Science 277 (5331): 1453–1462. doi:10.1126/science.277.5331.1453. PMID 9278503. http://www.sciencemag.org/cgi/content/abstract/277/5331/1453.
  8. ScienceShot: biggest genome ever, comments: "The measurement for Amoeba dubia and other protozoa, which were reported to have very large genomes, were made in the 1960s using a rough biochemical approach which is now considered to be an unreliable method for accurate genome size determinations".
  9. 9.0 9.1 Greilhuber J. et al. 2006. Smallest angiosperm genomes found in Lentibulariaceae, with chromosomes of bacterial size. Plant Biology. 8: 770-777.
  10. The C. elegans sequencing consortium (1998). "Genome sequence of the nematode C. elegans: a platform for investigating biology". Science 282: 2012–2018. http://www.sciencemag.org/cgi/content/abstract/282/5396/2012?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&searchid=1&FIRSTINDEX=0&volume=282&firstpage=2012&resourcetype=HWCIT.
  • Benfey P. and Protopapas A.D. 2004. Essentials of genomics. Prentice Hall.
  • Brown T.A. 2002. Genomes 2. Bios Scientific Publishers.
  • Gibson G. and Muse S.V. 2004. A primer of genome science. 2nd ed. Sinauer Assoc.
  • Gregory T.R. (ed) 2005. The evolution of the genome. Elsevier.
  • Reece R.J. 2004. Analysis of genes and genomes. Wiley.
  • Saccone C. and Pesole G. 2003. Handbook of comparative genomics. Wiley.
  • Werner E. 2003. In silico multicellular systems biology and minimal genomes. Drug Discov Today. 8(24):1121-7. PubMed
  • Witzany G. 2007. Natural genome editing competences of viruses. Acta Biotheoretica. [2]

Other websites[change | change source]