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2.2. Genes: from Mendel to molecular biology
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The notion of gene emerged withthe works of Gregor Mendel. Mendel studied the inheritance on some traits like the shape of pea plant seeds,through generations. He stated the famous laws of inheritance which, by the way, were rediscovered 50 years later. The important thing here tounderline is that these concepts of inheritance of genes and so on were very abstract. No physical supports ofthese genes were clarified. So, it's something which appearedlater through molecular biology. We now know that genes are thoseregions of DNA which code the
information used by the cell to produce proteins. And, this is what Francis Crick stated as the central dogma of molecular biology. One gene codes for one protein. We know now that this dogma is not valid anymore. We have several counter examples. But at that time, it was quite a reasonable hypothesis. A view of the central dogma is here. You have DNA and you have proteins. And a gene codes for one protein. Again it's not the whole truthbut it's a good approximation, especially for bacterial genome. But, there's this step here where DNA is first transcribed into RNA. And then, RNA is used by thecell to produce proteins.
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