A reverse transcriptase/polymerase chain reaction (RT/PCR) method for the construction of representative cDNA libraries originating from few isolated cells is described. Poly(A)+ RNA was extracted from an average of 100 maize cells and reverse transcribed into sscDNA. The sscDNA was dG-tailed at its 3' end and amplified during a two-step PCR reaction. The generated PCR products were analysed and the majority < or = 2 kbp were full-size cDNAs. A fraction of the amplified cDNA from 128 isolated maize egg cells was cloned into the lambda Uni-ZAP XR vector and a primary library of 6.8 x 10(6) p.f.u. was obtained. The average insert size is 860 bp. It was further determined, that 0.31% of the clones hybridized to a cytosolic GAPDH probe. It is thought that, with this method, the first cDNA library of egg cells in higher plants was generated.