As the human genome project continues toward its goal of sequencing the entire human genome by the end of 2003, this is providing unique opportunities for studying genetic variation in humans and its relationship with disease risk and aging. Consequently, new techniques have been invented to rapidly screen genes for biological information.Over the past few years, DNA microarrays have received considerable attention from both researchers and the public. DNA arrays represent a blossoming field, estimated to be worth $40 million a year and expected to grow 10 times that over the next few years. DNA arrays are the latest molecular biology technique to utilize nucleic acid hybridization as its basis. Two of the most common uses of the DNA arrays are 1) genetic analysis 2) and the analysis of gene expression. Genetic analysis includes procedures for genotyping, SNP (single nucleotide polymorphism) detection, strain identification, and various other procedures. Analysis of gene expression can include assessing expression levels of small sets of genes to whole genome expression monitoring. Depending on the design of the arrayed DNAs, other expression phenomena like differential RNA splicing can also be examined and analyzed on expression arrays. This report will focus on using medium density oligonucleotide DNA arrays for the analysis of gene expression.The majority of the actual slide making, printing, hybridization, probe making and post hybridization methods listed here are the same or slightly modified versions of the protocols found on the Stanford web site, http://cmgm.stanford.edu/pbrown/protocols/
. The changes made to the Stanford protocols are to accommodate oligonucleotides as the probes on the glass slide.