Cloning by limiting dilution: An improved estimate that an interesting culture is monoclonal

An interesting culture obtained by limiting dilution is less likely to be monoclonal than a random viable culture. Current practice using limiting dilution to establish monoclonal lines of interesting recom-binant DNA or hybridoma-derived organisms overestimates the probability that promising cultures are monoclonal, resulting in inadequate dilutions, with the need for additional sub-cloning and the avoidable loss (avoidable instability) of interesting lines by overgrowth with uninteresting varieties. In cloning by limiting dilution [1] it is often assumed that progenitors are Poisson-distributed and the probability that a resulting interesting culture is monoclonal is the same as that of any viable culture [2]. An improved estimate of the probability that a culture containing interesting cells is monoclonal can be obtained independent of cloning efficiency by assuming interesting and uninteresting progenitors inde-pendently Poisson-distributed and calculating the conditional probability that an interesting culture arose from a single progenitor. The probability an interesting culture is monoclonal is calculated in terms of the fractions of sterile and uninterest