03-08-2013, 04:29 PM
Bacterial and gene identification using DNA Microarray Technology (GENOMICS)
ABSTRACT
During the last decade, more than 86 microbial genomes have been completely sequenced and published (http://www.tigrtdb/mdb/mdbcomplete.html), and it is estimated that there are more than 179 microbial genome sequencing projects currently underway (http://www.tigrtdb/mdb/mdbinprogress.html). The sequenced microbial genomes provide large amounts of sequence data that can be used for fast and high-throughput screening technologies such as microarray printing. Screening technologies are highly efficient because they perform thousands of tests at the same time. In molecular microarray fabrication, small, nanoliter-size volumes are instantaneously arrayed so that simultaneous characterization of genes and bacteria can be achieved in a very short time. Publicly available sequences of bacterial genomes are used to synthesize 20to 70 single-strand nucleotide target sequences, representing different genes that are then spotted on glass slides. Two primers are designed by sequence alignment of conserved regions of gene families, and fluorescent-labeled DNA probes are amplified and then hybridized to the target sequence that has been spotted on the area of the glass slide conventionally called the “chip.” This strategy is used mainly for bacterial gene identification. A second approach to study gene expression relies on generating a chip spotted with 500- to 5000-bp PCR amplified fragments or synthesized single-strand oligonucleotides representing genes.