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DNA Sequencing. Kabi R. Neupane, Ph.D. Leeward Community College ABE Workshop 2006. What to Sequence?. The RT-PCR product has been inserted into the pCR4-TOPO vector Our goal -Sequence the insert DNA. We Supplied. Template DNA: Your plasmid Primer DNA: T3 or T7. Frederick Sanger.
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DNA Sequencing Kabi R. Neupane, Ph.D. Leeward Community College ABE Workshop 2006
What to Sequence? • The RT-PCR product has been inserted into the pCR4-TOPO vector • Our goal • -Sequence the insert DNA
We Supplied Template DNA: Your plasmid Primer DNA: T3 or T7
Frederick Sanger • Discovered DNA sequencing by chain termination method • Nobel Prize 1 (1958) • Complete amino acid sequence of insulin • Nobel Prize 2 (1980) • For DNA sequencing
DNA Polymerase Action • DNA Sequencing exploits the DNA polymerase activity for deciphering DNA sequence • Modern DNA sequence use PCR technology in sequencing T3 Primer ATTAACCC TCACTAAAGG DNA Polymerase GACTAGTCCT GCAGGTTTAA AGGAATTCGC CCTT
One primer PCR Reaction DNA Polymerase Primer dATP dGTP dCTP dGTP Nucleotides NEW STRAND Template DNA
Dideoxy Nucleotides • Lack an -OH group at the 3-carbon position • Cannot add another nucleoside at that position • Prevent further DNA synthesis
Dideoxy nucleotides • Incorporation of a dideoxynucleotide to growing DNA strand terminates its further extension • Are added in small proportion • dATP ddATP • dGTP ddGTP • dCTP ddCTP • dTTP ddTTP
Polyacrylamide Gel Electrophoresis Separates fragments based on size
Do not forget the other strand GGG ATATCACTCA GCATAATTGTTAAGTGACC T7 Primer
GenBank The Basic Local Alignment Search Tool (BLAST) finds regions of local similarity between sequences. http://www.ncbi.nlm.nih.gov/
Involves fragment assembly using computer algorithms Shotgun Sequencing Contigs