INTRODUCTION

The method of solid anchored PCR uses specific oligonucleotides coupled to a solid phase as primers for cDNA synthesis [1] and results in cDNA that is covalently linked to the solid phase such as agarose [1] , acrylamide [1] , magnetic [2-4] , or latex beads [5] . A solid phase with cDNA attached, generated using oligo (dT) as a primer, contains sequence information similar to a cDNA library, thus it represents a 'solid phase library' [1, 3, 4] . The cDNA that is attached to the solid phase can be used directly as a template for PCR reactions or can be modified enzymatically prior to the PCR reaction. Oligonucleotides that are attached to a solid phase can also serve for affinity purification of RNA [2] . RNA isolated this way can be directly reverse transcribed, using the primer that is coupled to the solid phase. Subsequent PCR reactions can employ this primer with or without additional internal primers. Since the cDNA is coupled to a solid phase, changing buffer conditions or primer composition is conveniently achieved by washing the solid phase and resuspending in a different PCR reaction mixture. The general principle of solid anchored PCR is shown in Figure 1.