Does Good Mutation Help You Live Longer?

TL;DR

This paper analyzes how mutations affecting life expectancy influence population longevity and fitness, revealing different growth patterns depending on mutational bias and a surprising inverse relation between population fitness and average age.

Contribution

It introduces a mathematical model of age-structured populations with mutational effects on life expectancy, highlighting new growth dynamics and age-fitness relationships.

Findings

Fitness grows linearly with time under advantageous mutations.

Fitness remains constant when mutations are neutral.

Average age stays finite and decreases as fitness increases.

Abstract

We study the dynamics of an age-structured population in which the life expectancy of an offspring may be mutated with respect to that of its parent. When advantageous mutation is favored, the average fitness of the population grows linearly with time $t$, while in the opposite case the average fitness is constant. For no mutational bias, the average fitness grows as t^{2/3}. The average age of the population remains finite in all cases and paradoxically is a decreasing function of the overall population fitness.