18 - Differential display

Abstract

This chapter discusses the technique of differential display (DD). It is a powerful technique to compare patterns of gene expression in ribonucleic acid (RNA) samples of different types or under different biological conditions. DD produces partial cDNA fragments by a combination of reverse transcription (RT) and polymerase chain reaction (PCR) of randomly primed RNA. Changes in the expression level of genes are identified after separation of cDNAs on sequencing-type gels. in comparison to the conventional differential and subtractive gene cloning methods, the DD technique offers several advantages. Moreover, it requires only small amounts of RNA and is very rapid. Though it is an effective technique, certain drawbacks are associated with the DD technique. This chapter highlights the aspects of sample preparation and the use of several control steps in the DD technique, which together markedly decrease the number of false positives. The chapter also mentions the aspects of the time-consuming postdifferential display work to validate putative candidate genes. Toward the end, the chapter presents certain problems of using the DD technique that will be faced in future.