Maria Stanislawa Magdon-Maksymowicz

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

Summary 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 of bad mutations. The idea is that biologically weaker individuals has got less 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 about 50 percent of the biological maximum lifespan for the standard Penna model, to about 40 percent. We also conclude that bad mutation distribution r(a) is altered so that younger individuals may accommodate significantly more bad mutations, up to 25 percent, as compared with the standard model (5 percent). In summary, it makes sense to force less productivity for older and weaker individuals.

New algorithm for the computation of the partition function for the Ising model on a square lattice

A new and efficient algorithm is presented for the calculation of the partition function in the

Epigenetic contribution to age distribution of mortality within the Penna model

S=\pm 1

Evolution of Population with Interaction between Neighbours

Ising model. As an example, we use the algorithm to obtain the thermal dependence of the magnetic spin susceptibility of an Ising antiferromagnet for a

Effect of time slowing in biological ageing

8\times 8

Stability of the analytical solution of Penna model of biological aging

square lattice with open boundary conditions. The results agree qualitatively with the prediction of the Monte Carlo simulations and with experimental data and they are better than the mean field approach results. For the

Population Growth in the Penna Model for Migrating Population

8\times 8

title

lattice, the algorithm reduces the computation time by nine orders of magnitude.A new and efficient algorithm is presented for the calculation of the partition function in the S=±1 Ising model. As an example, we use the algorithm to obtain the thermal-dependence of the magnetic spin susceptibility of an Ising antiferromagnet for a 8×8 square lattice with open boundary conditions. The results agree qualitatively with the prediction of the Monte Carlo simulations and the experimental data, and they are better than the mean field approach results. For the 8×8 lattice, the algorithm reduces the computation time by nine orders of magnitude.

ON THE EVOLUTION OF MIGRATING POPULATION WITH TWO COMPETING SPECIES

Some modifications of the simple asexual Penna model, enriched by epigenetic contributions, are presented. The standard bit-string Penna model of biological aging and population evolution is based on an inherited DNA structure which defines the future life of a newly born individuals, when genes are activated by the biological clock, and the predefined genetic death is fully controlled by the number of defected genes. Epigenomes allow to introduce additional mechanism of gene activation or silencing without affecting the DNA genome itself. It may be either inherited or may reflect external, environmental factors. In the presented model, information read from the introduced epigenome may alter gene expression that may be stopped or re-activated. We concentrate on the influence of epigenetics on the age