Differential RNA fingerprinting as a tool in the analysis of spermatozoal gene expression.

The apparent decline in human male fertility and the concomitant increase in testicular pathology have prompted discussion of the underlying molecular mechanisms which may underpin these observations. While monitoring the expression of protamine-2 genes in the human ejaculate, we found a representative complement of sperm mRNAs following sequence-independent amplification of reverse-transcribed cDNAs with the polymerase chain reaction (RT-PCR). The revelation of unique sperm-derived PCR products using this method suggests that it should now be possible to investigate gene expression in human spermatogenesis by differential RNA fingerprinting of ejaculate spermatozoa. The identification of molecular markers and the corresponding genes associated with male infertility will be considerably enhanced by these investigations while obviating the requirement for invasive biopsy.