Difference between revisions of "Team:Bordeaux/Software"

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   At the beginning of DNA sequencing in the 70’s, two main methods were developed. One of them by Walter Gilbert (USA) and another one by Frederick Sanger (UK), they both obtained the chemistry Nobel prize in 1980. The two approaches are really different and we will quickly sum them up.</p>
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   At the beginning of DNA sequencing in the 70’s, two main methods were developed. One of them by Walter Gilbert (USA) and another one by Frederick Sanger (UK), they both obtained the chemistry Nobel prize in 1980. From the 90’s several new methods were developed to increase the performances and decrease the costs of sequencing. These methods so called NGS methods opened new perspectives for biologists. This year, for the IGEM competition we focused on one of the based NGS method, which is RNA-Seq (Figure 1).
 
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    <b>Maxam and Gilbert method :</b> This method works in several steps. First, the two extremity of a double strand DNA (dsDNA) are radioactively labeled. Then the targeted DNA sequence is selected by polyacrylamide gel electrophoresis (PAGE). The two strands are separated by thermic denaturation and purified by PAGE. Some chemical modifications are performed on these strands in a way that each sample of DNA contain zero or one modification. The DNA is then cleaved by piperidine. Finally an electrophoresis allows to recomposing the initial sequence. The main problem with this method is the use or radioactivity and the toxic chemicals used.
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    <b>Sanger method :</b> This approach use a target DNA which will be incubated with a polymerase. This polymerase needs oligonucleotids to perform polymerisation. Sanger had the idea to use desoxyribonucleotids and a little quantity of didesoxyribonucleotids (ddNTP). When the polymerase incorporates a ddNTP the polymerisation stops. Thus a migration by electrophoresis allows to determine the initial DNA sequence.
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<p>
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  From the 90’s several new methods were developed to increase the performances and decrease the costs of sequencing. These methods so called NGS methods reduced costs and increased speed of sequencing, and thus opened new perspective for biologist. This year, for the IGEM competition we focused on one of the based NGS method, which is RNA-Seq (Figure 1).
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Revision as of 13:01, 1 November 2017

Wrong