RNA Expression Profiling
This chapter provides the reader with some basic background information about types of microarrays available, a practical overview to help navigate among the ever-increasing numbers of available tools and the techniques of filtering relevant information from the thousands of data points generated from microarray experiments. The cDNA probes can easily be generated by polymerase chain reaction amplification of plasmid deoxyribonucleic acid, and the resulting product can be purified over inexpensive purification columns and spotted on fairly inexpensive glass slides. The goal of a cross-sectional study is to identify genes or patterns of expression for diagnostic purposes or to identify relevant biochemical pathways. A very small number of genes are identified and correlated and therefore are predictive of the biological variables of interest. Single nucleotide polymorphism microarrays provide three types of genetic information: loss of hetero-zygosity, chromosomal copy number changes and genotype information.