Figure 4.

Quantitation of transcriptional episodes in latently infected lungs. (A) Poisson distribution analysis of clonality. Based on the fraction of tissue pieces negative for transcripts from the respective viral gene ( Figure 2 ), the Poisson distribution parameter λ = - lnF(0) allows the calculation of the numbers of clonal F(n=1), biclonal F(n=2) and oligoclonal F(n >2) transcription events according to the formula F(n) = λ/n x F(n-1). (B) Illustration of clonality for a “statistical lung”, representing the average of lungs derived from 5 mice per time of analysis.