Dna sequencing
-
Upload
lschroer -
Category
Technology
-
view
908 -
download
1
description
Transcript of Dna sequencing
![Page 1: Dna sequencing](https://reader035.fdocuments.in/reader035/viewer/2022062319/556c6a46d8b42ad85e8b4b4c/html5/thumbnails/1.jpg)
DNA SequencingLauren Schroer
![Page 2: Dna sequencing](https://reader035.fdocuments.in/reader035/viewer/2022062319/556c6a46d8b42ad85e8b4b4c/html5/thumbnails/2.jpg)
What is DNA Sequencing?
• DNA Sequencing is a technique used to determine the order of nucleotides in a gene.
![Page 3: Dna sequencing](https://reader035.fdocuments.in/reader035/viewer/2022062319/556c6a46d8b42ad85e8b4b4c/html5/thumbnails/3.jpg)
Steps in DNA Sequencing
• DNA Sequencing consists of four main steps:– Polymerase Chain Reaction (PCR)– Sequencing Reaction– Gel Electrophoresis – Computer Scanning
![Page 4: Dna sequencing](https://reader035.fdocuments.in/reader035/viewer/2022062319/556c6a46d8b42ad85e8b4b4c/html5/thumbnails/4.jpg)
Step 1: PCR
• Chromosomes (50-250 million bases long) are multiplied and broken up into shorter fragments.
![Page 5: Dna sequencing](https://reader035.fdocuments.in/reader035/viewer/2022062319/556c6a46d8b42ad85e8b4b4c/html5/thumbnails/5.jpg)
Step 2: Sequencing Reaction
• Reaction is done with dideoxyribonucleotides (just like regular DNA without 3’ hydroxyl group), which when added to the end make it impossible for the DNA to elongate.
• Restriction enzymes cut at these dideoxyribonucleotides. (Ex: Dideoxy-T)
• The place on the strand that is cut is random each time so eventually the cut strands will end with every individual T (or A,G, or C), in the sequence.
![Page 6: Dna sequencing](https://reader035.fdocuments.in/reader035/viewer/2022062319/556c6a46d8b42ad85e8b4b4c/html5/thumbnails/6.jpg)
Step 3: Gel Electrophoresis
• The fragments are set in and then separated by Gel Electrophoresis.
• Flourescent dyes are used to identify the end nucleotide (if it is an A, T, G, or C).
![Page 7: Dna sequencing](https://reader035.fdocuments.in/reader035/viewer/2022062319/556c6a46d8b42ad85e8b4b4c/html5/thumbnails/7.jpg)
Step 4: Computer Scanning
• Computers ‘read’ the sequence from the gel and interpret the colors and print a sequence of nucleotides across the top.
![Page 8: Dna sequencing](https://reader035.fdocuments.in/reader035/viewer/2022062319/556c6a46d8b42ad85e8b4b4c/html5/thumbnails/8.jpg)
Limitations
• Currently only 500-900 bases can be sequenced with each read.
• Less expensive methods are less accurate.
![Page 9: Dna sequencing](https://reader035.fdocuments.in/reader035/viewer/2022062319/556c6a46d8b42ad85e8b4b4c/html5/thumbnails/9.jpg)
Ethical Concerns
• Some people believe that a person’s DNA sequence is their business, and their business only, and if DNA sequencing becomes too common it could be abused.
![Page 10: Dna sequencing](https://reader035.fdocuments.in/reader035/viewer/2022062319/556c6a46d8b42ad85e8b4b4c/html5/thumbnails/10.jpg)
Sources• "How Do We Sequence DNA?" How Do We Sequence DNA? Web. 23
May 2012.<http://seqcore.brcf.med.umich.edu/doc/educ/dnapr/sequencing.html>.
• "Tiny Reader Makes Fast, Cheap DNA Sequencing Feasible." ScienceDaily. ScienceDaily, 26 Mar. 2012. Web. 23 May 2012. <http://www.sciencedaily.com/releases/2012/03/120326160651.htm>.
• "DNA Sequencing, Without the Fuss." ScienceNOW. Web. 23 May 2012. <http://news.sciencemag.org/sciencenow/2012/03/dna-
sequencing-without-the- fuss.html>.
![Page 11: Dna sequencing](https://reader035.fdocuments.in/reader035/viewer/2022062319/556c6a46d8b42ad85e8b4b4c/html5/thumbnails/11.jpg)
THE END