<p><strong>Genomics</strong> is the study of an organism's entire <a href="http://en.wikipedia.org/wiki/Genome" title="Genome">genome</a>. In contrast, the investigation of single genes, their functions and roles, something very common in today's medical and biological research, and a primary focus of <a href="http://en.wikipedia.org/wiki/Molecular_biology" title="Molecular biology">molecular biology</a>, does not fall into the definition of genomics, unless the aim of this genetic, pathway, and functional information analysis is to elucidate its effect on, place in, and response to the entire genome's networks.</p>  <p><a nameid="History_of_the_field" idname="History_of_the_field"></a></p>

<p>Genomics can be said to have appeared in the <a href="http://en.wikipedia.org/wiki/1980s" title="1980s">1980s</a>, and took off in the <a href="http://en.wikipedia.org/wiki/1990s" title="1990s">1990s</a> with the initiation of <a href="http://en.wikipedia.org/wiki/Genome_projects" title="Genome projects">genome projects</a> for several <a href="http://en.wikipedia.org/wiki/Biological_species" title="Biological species">biological species</a>. A major branch of genomics is still concerned with <a href="http://en.wikipedia.org/wiki/Sequencing" title="Sequencing">sequencing</a> the genomes of various organisms, but the knowledge of full genomes has created the possibility for the field of <a href="http://en.wikipedia.org/wiki/Functional_genomics" title="Functional genomics">functional genomics</a>, mainly concerned with patterns of <a href="http://en.wikipedia.org/wiki/Gene_expression" title="Gene expression">gene expression</a> during various conditions. The most important tools here are <a href="http://en.wikipedia.org/wiki/Microarray" title="Microarray">microarrays</a> and <a href="http://en.wikipedia.org/wiki/Bioinformatics" title="Bioinformatics">bioinformatics</a>. Study of the full set of proteins in a cell type or tissue, and the changes during various conditions, is called <a href="http://en.wikipedia.org/wiki/Proteomics" title="Proteomics">proteomics</a>.</p><p>In <a href="http://en.wikipedia.org/wiki/1972" title="1972">1972</a>, <a href="http://en.wikipedia.org/wiki/Walter_Fiers" title="Walter Fiers">Walter Fiers</a> and his team at the Laboratory of Molecular Biology of the <a href="http://en.wikipedia.org/wiki/University_of_Ghent" title="University of Ghent">University of Ghent</a> (<a href="http://en.wikipedia.org/wiki/Ghent" title="Ghent">Ghent</a>, <a href="http://en.wikipedia.org/wiki/Belgium" title="Belgium">Belgium</a>) were the first to determine the sequence of a gene: the gene for <a href="http://en.wikipedia.org/wiki/Bacteriophage_MS2" title="Bacteriophage MS2">Bacteriophage MS2</a> coat protein.<sup id="_ref-0" class="reference"><a hrefid="http://en.wikipedia.org/wiki/Genomics#_note_ref-0" title="">[1]</a></sup> In <a href="http://en.wikipedia.org/wiki/1976" title="1976">1976</a>, the team determined the complete nucleotide-sequence of bacteriophage MS2-RNA.<sup id="_ref-1" class="reference"><a hrefid="http://en.wikipedia.org/wiki/Genomics#_note_ref-1" title="">[2]</a></sup> The first DNA-based genome to be sequenced in its entirety was that of <a href="http://en.wikipedia.org/wiki/Bacteriophage" title="Bacteriophage">bacteriophage</a> <a href="http://en.wikipedia.org/wiki/Phi-X174_phage" title="Phi-X174 phage">&Phi;-X174;</a> (5,368 <a href="http://en.wikipedia.org/wiki/Base_pair" title="Base pair">bp</a>), sequenced by <a href="http://en.wikipedia.org/wiki/Frederick_Sanger" title="Frederick Sanger">Frederick Sanger</a> in <a href="http://en.wikipedia.org/wiki/1977" title="1977">1977</a><sup id="_ref-2" class="reference"><a hrefid="http://en.wikipedia.org/wiki/Genomics#_note_ref-2" title="">[3]</a></sup>. The first free-living organism to be sequenced was that of <em><a href="http://en.wikipedia.org/wiki/Haemophilus_influenzae" title="Haemophilus influenzae">Haemophilus influenzae</a></em> (1.8 <a href="http://en.wikipedia.org/wiki/Base_pair" title="Base pair">Mb</a>) in <a href="http://en.wikipedia.org/wiki/1995" title="1995">1995</a>, and since then genomes are being sequenced at a rapid pace. A rough draft of the human genome was completed by the <a href="http://en.wikipedia.org/wiki/Human_Genome_Project" title="Human Genome Project">Human Genome Project</a> in early <a href="http://en.wikipedia.org/wiki/2001" title="2001">2001</a>, creating much fanfare.</p><p>As of September 2007, the complete sequence was known of about 1879 <a href="http://en.wikipedia.org/wiki/Virus" title="Virus">viruses</a> <sup id="_ref-3" class="reference"><a hrefid="http://en.wikipedia.org/wiki/Genomics#_note_ref-3" title="">[4]</a></sup>, 577 <a href="http://en.wikipedia.org/wiki/Bacteria" title="Bacteria">bacterial</a> species and roughly 23 <a href="http://en.wikipedia.org/wiki/Eukaryote" title="Eukaryote">eukaryote</a> organisms, of which about half are <a href="http://en.wikipedia.org/wiki/Fungi" title="Fungi">fungi</a>. <sup id="_ref-4" class="reference"><a hrefid="http://en.wikipedia.org/wiki/Genomics#_note_ref-4" title="">[5]</a></sup> Most of the bacteria whose genomes have been completely sequenced are problematic disease-causing agents, such as <em><a href="http://en.wikipedia.org/wiki/Haemophilus_influenzae" title="Haemophilus influenzae">Haemophilus influenzae</a></em>. Of the other sequenced species, most were chosen because they were well-studied model organisms or promised to become good models. Yeast (<em><a href="http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae" title="Saccharomyces cerevisiae">Saccharomyces cerevisiae</a></em>) has long been an important <a href="http://en.wikipedia.org/wiki/Model_organism" title="Model organism">model organism</a> for the <a href="http://en.wikipedia.org/wiki/Eukaryotic_cell" title="Eukaryotic cell">eukaryotic cell</a>, while the fruit fly <em><a href="http://en.wikipedia.org/wiki/Drosophila_melanogaster" title="Drosophila melanogaster">Drosophila melanogaster</a></em> has been a very important tool (notably in early pre-molecular <a href="http://en.wikipedia.org/wiki/Genetics" title="Genetics">genetics</a>). The worm <em><a href="http://en.wikipedia.org/wiki/Caenorhabditis_elegans" title="Caenorhabditis elegans">Caenorhabditis elegans</a></em> is an often used simple model for <a href="http://en.wikipedia.org/wiki/Multicellular_organism" title="Multicellular organism">multicellular organisms</a>. The zebrafish <em><a href="http://en.wikipedia.org/wiki/Brachydanio_rerio" title="Brachydanio rerio">Brachydanio rerio</a></em> is used for many developmental studies on the molecular level and the flower <em><a href="http://en.wikipedia.org/wiki/Arabidopsis_thaliana" title="Arabidopsis thaliana">Arabidopsis thaliana</a></em> is a model organism for flowering plants. The <a href="http://en.wikipedia.org/w/index.php?title=Japanese_pufferfish&amp;action=edit" class="new" title="Japanese pufferfish">Japanese pufferfish</a> (<em><a href="http://en.wikipedia.org/wiki/Takifugu_rubripes" title="Takifugu rubripes">Takifugu rubripes</a></em>) and the <a href="http://en.wikipedia.org/w/index.php?title=Spotted_green_pufferfish&amp;action=edit" class="new" title="Spotted green pufferfish">spotted green pufferfish</a> (<em><a href="http://en.wikipedia.org/wiki/Tetraodon_nigroviridis" title="Tetraodon nigroviridis">Tetraodon nigroviridis</a></em>) are interesting because of their small and compact genomes, containing very little non-coding DNA compared to most species. <sup id="_ref-5" class="reference"><a hrefid="http://en.wikipedia.org/wiki/Genomics#_note_ref-5" title="">[6]</a></sup> <sup id="_ref-6" class="reference"><a hrefid="http://en.wikipedia.org/wiki/Genomics#_note_ref-6" title="">[7]</a></sup> The mammals dog (<em><a href="http://en.wikipedia.org/wiki/Canis_familiaris" title="Canis familiaris">Canis familiaris</a></em>), <sup id="_ref-7" class="reference"><a hrefid="http://en.wikipedia.org/wiki/Genomics#_note_ref-7" title="">[8]</a></sup> brown rat (<em><a href="http://en.wikipedia.org/wiki/Rattus_norvegicus" title="Rattus norvegicus">Rattus norvegicus</a></em>), mouse (<em><a href="http://en.wikipedia.org/wiki/Mus_musculus" title="Mus musculus">Mus musculus</a></em>), and chimpanzee (<em><a href="http://en.wikipedia.org/wiki/Pan_troglodytes" title="Pan troglodytes">Pan troglodytes</a></em>) are all important model animals in medical research.</p><p><a nameid="Bacteriophage_Genomics" idname="Bacteriophage_Genomics"></a></p>

<p><a href="http://en.wikipedia.org/wiki/Bacteriophage" title="Bacteriophage">Bacteriophages</a> have played and continue to play a key role in bacterial <a href="http://en.wikipedia.org/wiki/Genetics" title="Genetics">genetics</a> and <a href="http://en.wikipedia.org/wiki/Molecular_biology" title="Molecular biology">molecular biology</a>. Historically, they were used to define <a href="http://en.wikipedia.org/wiki/Gene" title="Gene">gene</a> structure and gene regulation. Also the first <a href="http://en.wikipedia.org/wiki/Genome" title="Genome">genome</a> to be sequenced was a <a href="http://en.wikipedia.org/wiki/Bacteriophage" title="Bacteriophage">bacteriophage</a>. However, bacteriophage research did not lead the genomics revolution, which is clearly dominated by bacterial genomics. Only very recently has the study of bacteriophage genomes become prominent, thereby enabling researchers to understand the mechanisms underlying <a href="http://en.wikipedia.org/wiki/Phage" title="Phage">phage</a> evolution. Bacteriophage genome sequences can be obtained through direct sequencing of isolated bacteriophages, but can also be derived as part of microbial genomes. Analysis of bacterial genomes has shown that a substantial amount of microbial DNA consists of <a href="http://en.wikipedia.org/wiki/Prophage" title="Prophage">prophage</a> sequences and prophage-like elements. A detailed database mining of these sequences offers insights into the role of prophages in shaping the bacterial genome.<sup id="_ref-McGrath_0" class="reference"><a hrefid="http://en.wikipedia.org/wiki/Genomics#_note_ref-McGrath" title="McGrath_0">[9]</a></sup></p><p><a nameid="Cyanobacteria_Genomics" idname="Cyanobacteria_Genomics"></a></p>

<p>At present there are 24 <a href="http://en.wikipedia.org/wiki/Cyanobacteria" title="Cyanobacteria">cyanobacteria</a> for which a total genome sequence is available. 15 of these cyanobacteria come from the marine environment. These are six <em><a href="http://en.wikipedia.org/wiki/Prochlorococcus" title="Prochlorococcus">Prochlorococcus</a></em> strains, seven marine <em><a href="http://en.wikipedia.org/wiki/Synechococcus" title="Synechococcus">Synechococcus</a></em> strains, <em><a href="http://en.wikipedia.org/w/index.php?title=Trichodesmium_erythraeum&amp;action=edit" class="new" title="Trichodesmium erythraeum">Trichodesmium erythraeum</a></em> IMS101 and <em><a href="http://en.wikipedia.org/w/index.php?title=Crocosphaera_watsonii&amp;action=edit" class="new" title="Crocosphaera watsonii">Crocosphaera watsonii</a></em> [[WH8501. Several studies have demonstrated how these sequences could be used very successfully to infer important ecological and physiological characteristics of marine cyanobacteria. However, there are many more genome projects currently in progress, amongst those there are further <em><a href="http://en.wikipedia.org/wiki/Prochlorococcus" title="Prochlorococcus">Prochlorococcus</a></em> and marine <em><a href="http://en.wikipedia.org/wiki/Synechococcus" title="Synechococcus">Synechococcus</a></em> isolates, <em><a href="http://en.wikipedia.org/w/index.php?title=Acaryochloris&amp;action=edit" class="new" title="Acaryochloris">Acaryochloris</a></em> and <em><a href="http://en.wikipedia.org/w/index.php?title=Prochloron&amp;action=edit" class="new" title="Prochloron">Prochloron</a></em>, the N₂-fixing filamentous cyanobacteria <em><a href="http://en.wikipedia.org/w/index.php?title=Nodularia_spumigena&amp;action=edit" class="new" title="Nodularia spumigena">Nodularia spumigena</a></em>, <em><a href="http://en.wikipedia.org/w/index.php?title=Lyngbya_aestuarii&amp;action=edit" class="new" title="Lyngbya aestuarii">Lyngbya aestuarii</a></em> and <em><a href="http://en.wikipedia.org/wiki/Lyngbya_majuscula" title="Lyngbya majuscula">Lyngbya majuscula</a></em>, as well as <a href="http://en.wikipedia.org/wiki/Bacteriophage" title="Bacteriophage">bacteriophages</a> infecting marine cyanobaceria. Thus, the growing body of genome information can also be tapped in a more general way to address global problems by applying a comparative approach. Some new and exciting examples of progress in this field are the identification of genes for regulatory RNAs, insights into the evolutionary origin of <a href="http://en.wikipedia.org/wiki/Photosynthesis" title="Photosynthesis">photosynthesis</a>, or estimation of the contribution of horizontal gene transfer to the genomes that have been analyzed.<sup id="_ref-Herrero_0" class="reference"><a hrefid="http://en.wikipedia.org/wiki/Genomics#_note_ref-Herrero" title="Herrero_0">[10]</a></sup></p><p><a nameid="See_also" idname="See_also"></a></p>

<li>[[Omics]]<a href="http://en.wikipedia.org/wiki/Computational_genomics" title="Computational genomics"li>Computational genomics </ali>[[Functional genomics]]</li> <li>[[Computational genomics]] <a href="http://en.wikipedia.org/wiki/Nitrogenomics" title="Nitrogenomics"li>Nitrogenomics </ali>[[Nitrogenomics]] </li>

<p><a nameid="References" idname="References"></a></p>

<li id="_note-0"><strong><a title="" href="http://en.wikipedia.org/wiki/Genomics#_ref-0" title="">^</a></strong> Min Jou W, Haegeman G, Ysebaert M, Fiers W., Nucleotide sequence of the gene coding for the bacteriophage MS2 coat protein, Nature. 1972 May 12;237(5350):82-8</li> <li id="_note-1"><strong><a title="" href="http://en.wikipedia.org/wiki/Genomics#_ref-1" title="">^</a></strong> Fiers W et al., Complete nucleotide-sequence of bacteriophage MS2-RNA - primary and secondary structure of replicase gene, Nature, 260, 500-507, 1976</li> <li id="_note-2"><strong><a title="" href="http://en.wikipedia.org/wiki/Genomics#_ref-2" title="">^</a></strong> Sanger F, Air GM, Barrell BG, Brown NL, Coulson AR, Fiddes CA, Hutchison CA, Slocombe PM, Smith M., Nucleotide sequence of bacteriophage phi X174 DNA, Nature. 1977 Feb 24;265(5596):687-95</li> <li id="_note-3"><strong><a hreftitle="" href="http://en.wikipedia.org/wiki/Genomics#_ref-3" title="">^</a></strong> <a hrefclass="external text" title="http://www.ncbi.nlm.nih.gov/genomes/VIRUSES/virostat.html" classrel="external textnofollow" titlehref="http://www.ncbi.nlm.nih.gov/genomes/VIRUSES/virostat.html" rel="nofollow"><><em>The Viral Genomes Resource</em>, NCBI Friday, 14 September, 2007</a></li> <li id="_note-4"><strong><a title="" href="http://en.wikipedia.org/wiki/Genomics#_ref-4" title="">^</a></strong> <a hrefclass="external text" title="http://www.ncbi.nlm.nih.gov/genomes/static/gpstat.html" classrel="external textnofollow" titlehref="http://www.ncbi.nlm.nih.gov/genomes/static/gpstat.html" rel="nofollow"><em>Genome Project Statistic</em>, NCBI Friday, 14 September, 2007</a></li> <li id="_note-5"><strong><a title="" href="http://en.wikipedia.org/wiki/Genomics#_ref-5" title="">^</a></strong> <a hrefclass="external text" title="http://news.bbc.co.uk/1/hi/sci/tech/3760766.stm" classrel="external textnofollow" titlehref="http://news.bbc.co.uk/1/hi/sci/tech/3760766.stm" rel="nofollow">BBC article <em>Human gene number slashed</em> from Wednesday, 20 October, 2004</a></li> <li id="_note-6"><strong><a title="" href="http://en.wikipedia.org/wiki/Genomics#_ref-6" title="">^</a></strong> <a hrefclass="external text" title="http://www.cbse.ucsc.edu/news/2003/10/16/pufferfish_fruitfly/index.shtml" classrel="external textnofollow" titlehref="http://www.cbse.ucsc.edu/news/2003/10/16/pufferfish_fruitfly/index.shtml" rel="nofollow">CBSE News, Thursday October 16, 2003</a></li> <li id="_note-7"><strong><a title="" href="http://en.wikipedia.org/wiki/Genomics#_ref-7" title="">^</a></strong> <a hrefclass="http:external text" title="http://www.genome.gov/12511476" classrel="external textnofollow" titlehref="http://www.genome.gov/12511476" rel="nofollow">NHGRI, pressrelease of the publishing of the dog genome</a></li> <li id="_note-McGrath"><strong><a title="" href="http://en.wikipedia.org/wiki/Genomics#_ref-McGrath_0" title="">^</a></strong> <cite class="book" style="fontFONT-styleSTYLE: normal;">Mc Grath S and van Sinderen D (editors). (2007). <em><a hrefclass="external text" title="http://www.horizonpress.com/phage" classrel="external textnofollow" titlehref="http://www.horizonpress.com/phage" rel="nofollow">Bacteriophage: Genetics and Molecular Biology</a></em>, 1st ed., Caister Academic Press. <a hrefclass="httpexternal text" title="http://www.horizonpress.com/phage" classrel="external textnofollow" titlehref="http://www.horizonpress.com/phage" rel="nofollow">ISBN 978-1-904455-14-1</a> .</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=book&amp;rft.btitle=Bacteriophage%3A+Genetics+and+Molecular+Biology&amp;rft.au=Mc+Grath+S+and+van+Sinderen+D+%28editors%29.&amp;rft.edition=1st+ed.&amp;rft.pub=Caister+Academic+Press&amp;rft_id=http%3A%2F%2Fwww.horizonpress.com%2Fphage">&nbsp;</span></li> <li id="_note-Herrero"><strong><a title="" href="http://en.wikipedia.org/wiki/Genomics#_ref-Herrero_0" title="">^</a></strong> <cite class="book" style="fontFONT-styleSTYLE: normal;">Herrero A and Flores E (editor). (2008). <em><a hrefclass="external text" title="http://www.horizonpress.com/cyan" classrel="external textnofollow" titlehref="http://www.horizonpress.com/cyan" rel="nofollow">The Cyanobacteria: Molecular Biology, Genomics and Evolution</a></em>, 1st ed., Caister Academic Press. <a hrefclass="external text" title="http://www.horizonpress.com/cyan" classrel="external textnofollow" titlehref="http://www.horizonpress.com/cyan" rel="nofollow">ISBN 978-1-904455-15-8</a> .</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=book&amp;rft.btitle=The+Cyanobacteria%3A+Molecular+Biology%2C+Genomics+and+Evolution&amp;rft.au=Herrero+A+and+Flores+E+%28editor%29.&amp;rft.edition=1st+ed.&amp;rft.pub=Caister+Academic+Press&amp;rft_id=http%3A%2F%2Fwww.horizonpress.com%2Fcyan"> <br />