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<p><strong>Genetics</strong> (from the <a title="Greek language" href="http://en.wikipedia.org/wiki/Greek_language"><font color="#0066cc">Greek</font></a> <em>genno</em> <strong>γεννώ</strong> = give birth) is the <a title="Science" href="http://en.wikipedia.org/wiki/Science"><font color="#0066cc">science</font></a> of <a title="Gene" href="http://en.wikipedia.org/wiki/Gene"><font color="#0066cc">genes</font></a>, <a title="Heredity" href="http://en.wikipedia.org/wiki/Heredity"><font color="#0066cc">heredity</font></a>, and the <a title="Variation" href="http://en.wikipedia.org/wiki/Variation"><font color="#0066cc">variation</font></a> of <a title="Organism" href="http://en.wikipedia.org/wiki/Organism"><font color="#0066cc">organisms</font></a>.<sup class="reference" id="_ref-Hartl_and_Jones_0"><a title="" href="http://en.wikipedia.org/wiki/Genetics#_note-Hartl_and_Jones"><font color="#0066cc">[1]</font></a></sup><sup class="reference" id="_ref-0"><a title="" href="http://en.wikipedia.org/wiki/Genetics#_note-0"><font color="#0066cc">[2]</font></a></sup> The phenomenon of inheritance has been implicitly utilized in breeding of organisms and selection for desired traits, and the scientific field of genetics seeks to understand the mechanisms of inheritance.</p><p>The genetic information of organisms is contained within the chemical structure of <a title="DNA" href="http://en.wikipedia.org/wiki/DNA"><font color="#0066cc">DNA</font></a> (deoxyribonucleic acid) molecules. Individually inherited traits, corresponding to regions in the DNA sequence, are called <a title="Genes" href="http://en.wikipedia.org/wiki/Genes"><font color="#0066cc">genes</font></a>. Genes encode the information necessary for synthesizing <a title="Proteins" href="http://en.wikipedia.org/wiki/Proteins"><font color="#0066cc">proteins</font></a> -- complex molecules generally responsible for enzymatic reactions, synthesis, communication and structure within a cell. DNA sequence is transcribed into an intermediate molecule called "<a title="Messenger RNA" href="http://en.wikipedia.org/wiki/Messenger_RNA"><font color="#0066cc">messenger RNA</font></a>", and <a title="Ribosomes" href="http://en.wikipedia.org/wiki/Ribosomes"><font color="#0066cc">ribosomes</font></a> translate this sequence to form a chain of amino acids to form a <a title="Protein" href="http://en.wikipedia.org/wiki/Protein"><font color="#0066cc">protein</font></a>. This process is known as the <a title="Central dogma of molecular biology" href="http://en.wikipedia.org/wiki/Central_dogma_of_molecular_biology"><font color="#0066cc">central dogma of molecular biology</font></a>.</p><p>Although genetics plays a large role in determining the appearance and behavior of organisms, it is the interaction of genetics with the environment that determines the ultimate outcome. Thus, while <a title="Twin" href="http://en.wikipedia.org/wiki/Twin"><font color="#0066cc">identical twins</font></a> have the same DNA and genes, differences in their experiences during development and childhood results in different <a class="extiw" title="wiktionary:personality" href="http://en.wiktionary.org/wiki/personality"><font color="#0066cc">personalities</font></a> and <a title="Fingerprint" href="http://en.wikipedia.org/wiki/Fingerprint"><font color="#0066cc">fingerprints</font></a>. <a id="History" name="History"></ap>
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<h2><span class="mw-headline">History</span></h2>
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<p><a title="Gregor Johann Mendel" href="http://en.wikipedia.org/wiki/Gregor_Johann_Mendel"><font color="#0066cc">Gregor Johann Mendel</font></a>, a German-Czech <a title="Augustinian" href="http://en.wikipedia.org/wiki/Augustinian"><font color="#0066cc">Augustinian</font></a> monk and scientist, is often called the "father of modern genetics", a title given to him due to his early work on the heredity of plants. In his paper "Versuche über Pflanzenhybriden" ("<a title="Experiments on Plant Hybridization" href="http://en.wikipedia.org/wiki/Experiments_on_Plant_Hybridization"><font color="#0066cc">Experiments on Plant Hybridization</font></a>"), presented in <a title="1865" href="http://en.wikipedia.org/wiki/1865"><font color="#0066cc">1865</font></a> to the Brunn Natural History Society, <a title="Gregor Mendel" href="http://en.wikipedia.org/wiki/Gregor_Mendel"><font color="#0066cc">Gregor Mendel</font></a> traced the inheritance patterns of certain traits in pea plants and showed that they could be described mathematically.<sup class="reference" id="_ref-mendel_0"><a title="" href="http://en.wikipedia.org/wiki/Genetics#_note-mendel"><font color="#0066cc">[3]</font></a></sup> Although not all features show these patterns of <a title="Mendelian inheritance" href="http://en.wikipedia.org/wiki/Mendelian_inheritance"><font color="#0066cc">Mendelian inheritance</font></a>, his work suggested the utility of the application of statistics to the study of inheritance.</p>
<p>The significance of Mendel's observations was not understood until early in the twentieth century, after his death, when his research was re-discovered by other scientists working on similar problems. The word "genetics" itself was coined by <a title="William Bateson" href="http://en.wikipedia.org/wiki/William_Bateson"><font color="#0066cc">William Bateson</font></a>, a significant proponent of Mendel's work, in a letter to <a title="Adam Sedgwick" href="http://en.wikipedia.org/wiki/Adam_Sedgwick"><font color="#0066cc">Adam Sedgwick</font></a>, dated <a title="April 18" href="http://en.wikipedia.org/wiki/April_18"><font color="#0066cc">April 18</font></a>, <a title="1905" href="http://en.wikipedia.org/wiki/1905"><font color="#0066cc">1905</font></a>.<sup class="reference" id="_ref-1"><a title="" href="http://en.wikipedia.org/wiki/Genetics#_note-1"><font color="#0066cc">[4]</font></a></sup> Bateson promoted the term "genetics" publicly in his inaugural address to the Third International Conference on Plant Hybridization (London, England) in 1906.<sup class="reference" id="_ref-bateson_genetics_0"><a title="" href="http://en.wikipedia.org/wiki/Genetics#_note-bateson_genetics"><font color="#0066cc">[5]</font></a></sup></p><p>In the decades following rediscovery and popularization of Mendel's work, numerous experiments sought to elucidate the molecular basis of DNA. In 1910 <a title="Thomas Hunt Morgan" href="http://en.wikipedia.org/wiki/Thomas_Hunt_Morgan"><font color="#0066cc">Thomas Hunt Morgan</font></a> argued that genes reside on chromosomes, based observations of a sex-linked white eye mutation in fruit flies. In 1913 his student <a title="Alfred Sturtevant" href="http://en.wikipedia.org/wiki/Alfred_Sturtevant"><font color="#0066cc">Alfred Sturtevant</font></a> used the phenomenon of <a title="Genetic linkage" href="http://en.wikipedia.org/wiki/Genetic_linkage"><font color="#0066cc">genetic linkage</font></a> and the associated recombination rates to demonstrate and map the linear arrangement of genes upon the chromosome.</p>
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<div class="thumbinner" style="WIDTH: 302px"><a class="internal" title="The chemical structure of DNA." href="http://en.wikipedia.org/wiki/Image:DNA_chemical_structure.svg"><img class="thumbimage" height="350" alt="The chemical structure of DNA." width="300" longdesc="/wiki/Image:DNA_chemical_structure.svg" src="http://upload.wikimedia.org/wikipedia/commons/thumb/e/e4/DNA_chemical_structure.svg/300px-DNA_chemical_structure.svg.png" /></a>