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lecture_notes:03-31-2010 [2010/04/01 18:17] galt |
lecture_notes:03-31-2010 [2010/04/02 18:16] jstjohn |
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**This post was copied from [[lecture_notes:Mar31|this original source location]]** | **This post was copied from [[lecture_notes:Mar31|this original source location]]** | ||
- | Nader talked about the chemistry behind 4 Sequencing Platforms : SOLiD Bioanalyzer, 454, Illumina/Solexa, and charge based detection system Now sequencing.\\ | + | Nader talked about the chemistry behind 4 Sequencing Platforms : SOLiD Bioanalyzer, 454, Illumina/Solexa, and charge perturbation detection system Now sequencing.\\ |
Sequencing workflow : Genomic DNA -> fragment -> amplification -> immobilization -> Sequencing.\\ | Sequencing workflow : Genomic DNA -> fragment -> amplification -> immobilization -> Sequencing.\\ | ||
Time required for sequencing through these platforms is :\\ | Time required for sequencing through these platforms is :\\ | ||
- | 1-2 hrs for CBD.\\ | + | 1-2 hrs for CPD.\\ |
9 hrs for 454.\\ | 9 hrs for 454.\\ | ||
3-7 days for Illumina/Solexa.\\ | 3-7 days for Illumina/Solexa.\\ | ||
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The underlying technolgies for the platforms :\\ | The underlying technolgies for the platforms :\\ | ||
- | * Sequencing by synthesis (SBS) : 454, Illumina/Solexa, Helicos, Pacbio, Charge based detection system Now Sequencing.\\ | + | * Sequencing by synthesis (SBS) : 454, Illumina/Solexa, Helicos, Pacbio, Charge Perturbation Detection system Now Sequencing.\\ |
* Sequencing by ligation : SOLiD.\\ | * Sequencing by ligation : SOLiD.\\ | ||
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**Mate-Pairing** - The chances of damage to DNA increases with time. Hence, there is a high possibility of not getting the accurate sequence data from the other end of DNA. To avoid this, the Mate-Pairing process involves the determination of sequence of DNA from the end towards the beginning and then from the beginning towards the end.\\ | **Mate-Pairing** - The chances of damage to DNA increases with time. Hence, there is a high possibility of not getting the accurate sequence data from the other end of DNA. To avoid this, the Mate-Pairing process involves the determination of sequence of DNA from the end towards the beginning and then from the beginning towards the end.\\ | ||
- | |||
- | ==== Alternative Notes ==== | ||
- | |||
- | === High Level Overview === | ||
- | |||
- | The high level sequencing workflow for all next gen tools is as follows: | ||
- | Fragment Sample -> Amplify Fragments -> Sequence Fragments | ||
- | |||
- | There are two main flavors of next generation sequencing technology: | ||
- | * Sequencing by Synthesis (SBS) | ||
- | * Hybridization | ||
- | |||
- | === Examination of Individual Technologies === | ||
- | |||
- | There are four technologies that were talked about today. | ||
- | * Pyrosequencing (454) | ||
- | * solid | ||
- | * Illumina/solexa | ||
- | * Ion Torrent | ||
== Pyrosequencing (SBS) == | == Pyrosequencing (SBS) == | ||
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There is a problem with multiple A's because of the modified nucleotides which are needed for this reaction. FIXME | There is a problem with multiple A's because of the modified nucleotides which are needed for this reaction. FIXME | ||
- | You must get the ammount of template on the beads just right. Must be all the same type. If too much template is present the read length is shortened (not sure why). If too few template is on the beads then the washing step will take away a significant amount of template and you won't have enough of a signal. | + | You must get the amount of template on the beads just right. Must be all the same type. If too much template is present the read length is shortened (not sure why). If too few template is on the beads then the washing step will take away a significant amount of template and you won't have enough of a signal. |
The packing beads that are placed around the bead which holds the template strands in the individual wells on the plate are what hold the various enzymes (other than the polymerase) needed for the reaction. | The packing beads that are placed around the bead which holds the template strands in the individual wells on the plate are what hold the various enzymes (other than the polymerase) needed for the reaction. | ||
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== Ion Torrent (SBS) == | == Ion Torrent (SBS) == | ||
- | Works very similarly to pyrosequencing, except rather than requiring light from luciferase enzymes it takes advantage of the proton that is released when a nucleotide is added to a template. It measures this electric current. The presense of a current over a certain template when a specific nucleotide is added to solution tells you that that nucleotide was added to that template. The level of current at a template tells you the number of nucleotides that were added in that run. | + | Works very similarly to pyrosequencing, except rather than requiring light from luciferase enzymes it takes advantage of the proton that is released when a nucleotide is added to a template. It measures this electric current. The presence of a current over a certain template when a specific nucleotide is added to solution tells you that that nucleotide was added to that template. The level of current at a template tells you the number of nucleotides that were added in that run. |
Can sequence about 60 bases every 100 minutes. | Can sequence about 60 bases every 100 minutes. |