At. Bernardes et D. Stauffer, MONTE-CARLO SIMULATION OF AGING - BEYOND BIT-STRING MODELS, International journal of modern physics C, 6(6), 1995, pp. 789-806
Penna's bit-string model of biological ageing due to the accumulation
of deleterious mutations is generalized to allow for more than one dis
ease per year. The results remain qualitatively unchanged except for a
more complicated non-monotonic approach to equilibrium. We also look
at ''mutational meltdown'', the extinction of the whole population if
all mutations are deleterious and heritable, and why the Penna model c
an escape this extinction. No dependence on population size is found f
or mutational meltdown, with up to 10(8) individuals.