12.7 Functional Genomics 25 44200 GRIFFITHS FREEM Ch-12 First Pages Sen 12-10-2003 p 25 Application File on File chip. The DNA is dried and treated so that it will bind to the glass. Many thousands of samples can be applied to one chip. In one approach, the array of DNAs consists of all known cDNAs from the genome. Another type of array is of oligonucleotides chemically synthesized in situ on the chip itself. Such arrays are exposed to a probe, for example, one consisting of the total set of RNA molecules extracted from a particular cell type at a specific stage in development. Fluorescent labels are at-tached to the probe, and the binding of the probe mole-cules to the homologous DNA spots on the glass chip is monitored automatically with the use of a laser-beam-illuminated microscope. Typical results are shown in Fig-ure 12-27. In this way, the genes that are active at any stage of development or under any environmental con-dition can be assayed. The idea is to identify protein net-works that are active in the cell at any particular stage of interest. Figure 12-28 shows an example of a develop-mental expression pattern generated by assaying this kind of chip. Note that these DNA array methods basically take
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This note was uploaded on 01/10/2011 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.