Catastrophic senescence and semelparity in the Penna aging model

TL;DR

This paper investigates how mutation accumulation influences aging patterns in the Penna model, revealing that catastrophic senescence depends on reproductive age and mutation threshold, with implications for understanding semelparity.

Contribution

It demonstrates that the severity of senescence in the Penna model is influenced by both reproductive strategy and genetic mutation thresholds, extending previous findings.

Findings

Senescence is catastrophic when mutation threshold T is less than or equal to reproduction age R.

Gradual aging occurs when the organism's mutation tolerance increases.

The timing of survival rate decline depends on the mutation threshold relative to R.

Abstract

The catastrophic senescence of the Pacific salmon is among the initial tests used to validate the Penna aging model. Based on the mutation accumulation theory, the sudden decrease in fitness following reproduction may be solely attributed to the semelparity of the species. In this work, we report other consequences of mutation accumulation. Contrary to earlier findings, such dramatic manifestation of aging depends not only on the choice of breeding strategy but also on the value of the reproduction age, R, and the mutation threshold, T. Senescence is catastrophic when $T \leq R$. As the organism's tolerance for harmful genetic mutations increases, the aging process becomes more gradual. We observe senescence that is threshold dependent whenever T>R. That is, the sudden drop in survival rate occurs at age equal to the mutation threshold value.