01:119:115 Lecture Notes - Lecture 13: Molecular Cloning, Polyacrylamide Gel Electrophoresis, Frederick Sanger
15 Mar 2016
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Document Summary
Dna technology facilitates the sequencing and manipulation of organisms" dna and analysis of gene expression. Frederick sanger method of dna sequencing fig 20. 3. Can sequence fragments between 800 and 1000 base pairs (bp) in length. Synthesis of each new strand starts at 3" end of primer and continues until a dideoxyribonucleotide is inserted (at random), preventing further elongation of the strand. A set of labeled strands of various lengths is generated, the color of label represents last nucleotide in each sequence. Labeled strands in mixture pass through sequencing machine through a polyacrylamide gel. Shorter strands move through quickly than longer ones; a sensor detects color of each. Most recent development in dn sequencing: does not rely on chain termination. Dna fragments (400-1000 bp) are amplified (copied) yielding large #s of identical fragments. Sequencing of the fragments can be done in parallel: allows for 100"s of millions of nucleotides to be sequenced within hours.
