Illegitimate transcription: Transcription of any gene in any cell type

Using in vitro amplification of cDNA by the polymerase chain reaction, the authors have detected spliced transcripts of various tissue-specific genes (genes for anti-Muellerian hormone, β-globin, aldolase A, and factor VIIIc) in human nonspecific cells, such as fibroblasts, hepatoma cells, and lymphoblasts. In rats, erythroid- and liver-type pyruvate kinase transcripts were also detected in brain, lung, and muscle. The abundance of these illegitimate transcripts is very low; yet, their existence and the possibility of amplifying them by the cDNA polymerase chain reaction provide a powerful tool to analyze pathological transcripts of any tissue-specific gene by using any accessible cell