Journal of Statistical Physics, Vol. 91, Nos. 5/6, 1998. p. 1055-1060.
The bit-string model of biological aging introduced by Penna is investigated. This is a well-established model, making use of mutation accumulation theory. However, it turns out that a correct use of the Verhulst factor is not made and therefore in a certain limiting case the model does not produce proper results. Furthermore, care has to be taken when chosing the time steps in the model to avoid unrealistic effects.