Biological ageing with birth rate controlled by mutations in the Penna model

Within the Penna model, we assume a modification with a reproduction rate B that depends on the health state of the individual defined by the number o f bad mutations. The idea is that biologically weaker individuals has got l ess chance to produce offsprings. The results obtained from simulations and for typical set of model parameters show that then the mortality rate q(a) is increasing faster with age a. The maximum age is also limited from abou t 50 percent of the biological maximum lifespan for the standard Penna mode l, to about 40 percent. We also conclude that bad mutation distribution r(a ) is alte;ed so that younger individuals may accommodate significantly more bad mutations, up to 25 percent, as compared with the standard model (5 pe rcent). In summary, it makes sense to force less productivity for older and weaker individuals.