ABSTRACT
This chapter discusses differential analysis of gene expression data. The main mechanism for regulating the activity of genes is by controlling their expression levels using Transcription Factors. The expression level of each gene can vary at different stages during cell formation and in different types of cells. The introduction of microarray technology enabled researchers to measure the expression levels of hundreds or thousands of genes in a genome at once. It enabled detection not only of individual genes that differ in expression, but of groups of genes that are expressed similarly, thus gradually shifting the interest from analysis of single molecules to large complexes and gene networks. Microarray technology utilizes the hybridization principle that underlies the double strand structure of the DNA and the DNA replication process. A typical analysis of a microarray dataset involves many pairwise comparisons of expression profiles.
