Modelling survival and allele complementation in the evolution of genomes with polymorphic loci

TL;DR

This study uses simulations to explore how polymorphic loci and allele complementation influence genome evolution in sexually reproducing populations under varying environmental conditions.

Contribution

It introduces a model of diploid genome evolution with polymorphic loci, highlighting the role of environment and recombination in allele diversity and population survival.

Findings

Polymorphic alleles increase with low recombination in changing environments.

Heterozygous loci tend to maintain allele complementarity over time.

Rapid environmental changes can lead to population extinction.

Abstract

We have simulated the evolution of sexually reproducing populations composed of individuals represented by diploid genomes. A series of eight bits formed an allele occupying one of 128 loci of one haploid genome (chromosome). The environment required a specific activity of each locus, this being the sum of the activities of both alleles located at the corresponding loci on two chromosomes. This activity is represented by the number of bits set to zero. In a constant environment the best fitted individuals were homozygous with alleles' activities corresponding to half of the environment requirement for a locus (in diploid genome two alleles at corresponding loci produced a proper activity). Changing the environment under a relatively low recombination rate promotes generation of more polymorphic alleles. In the heterozygous loci, alleles of different activities complement each other fulfilling the environment requirements. Nevertheless, the genetic pool of populations evolves in the direction of a very restricted number of complementing haplotypes and a fast changing environment kills the population. If simulations start with all loci heterozygous, they stay heterozygous for a long time.