From the Columbia University web site of Associate Professor Jingyue Ju comes a description of a massively parallel DNA sequencing method.
Fluorescence Imaging Chip System for Massive Parallel DNA Sequencing. The use of electrophoresis for DNA sequencing has been a major bottleneck for high-throughput DNA sequencing projects. The need for electrophoresis is eliminated when sequencing DNA by synthesis, that is, when detecting the identity of each nucleotide as it is incorporated into the growing strand of DNA in a polymerase reaction. Such a scheme, if coupled to the chip format, has the potential to markedly increase the throughput of sequencing projects. Our laboratory is developing a chip-based 'sequencing by synthesis' platform. This DNA sequencing system includes the construction of a chip with immobilized single stranded DNA templates that can self prime for the generation of the complementary DNA strand in polymerase reaction, and 4 unique fluorescently labeled nucleotide analogues with 3'-OH capped by a small chemical moiety to allow efficient incorporation into the growing strand of DNA as terminators in the polymerase reaction. A 4-color fluorescence imager is then used to identify the sequence of the incorporated nucleotide on each spot of the chip. Upon removing the dye photochemically and the 3'-OH capping group, the polymerase reaction will proceed to incorporate the next nucleotide analogue and detect the next base. It is a routine procedure now to immobilize high density (>10,000 spots per chip) single stranded DNA on a 4cm x 1cm glass chip. Thus, in the chip based DNA sequencing system, more than 10,000 bases will be identified after each cycle and after 100 cycles million of base pairs will be generated from one sequencing chip. Massively parallel DNA sequencing promises to bring genetic analysis to the next level where we can envision, for example, the comparison on individual genome profiles.
|Share |||Randall Parker, 2002 November 06 05:39 PM Biotech Advance Rates|