Numerous studies based on new single-cell and single-gene techniques show that individual genes can be transcribed in short bursts or pulses accompanied by changes in pulsing frequencies. Since so many examples of such discontinuous or fluctuating transcription have been found from prokaryotes to mammals, it now seems to be a common mode of gene expression. In this review we discuss the occurrence of the transcriptional fluctuations, the techniques used for their detection, their putative causes, kinetic characteristics, and probable physiological significance.

Institute of Biology and Medical Genetics 1st Faculty of Medicine Charles University and General University Hospital Prague Prague Czech Republic

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Variability of Human rDNA

Discontinuous transcription of ribosomal DNA in human cells