The role of haplotype complementation and purifying selection in the genome evolution

TL;DR

This paper explores how haplotype complementation and purifying selection influence genome evolution, highlighting the effects of population size, recombination, and gene clustering on genetic diversity and chromosome structure.

Contribution

It introduces the concept of a phase transition between complementation and purification strategies and links this to observed recombination patterns and speciation processes.

Findings

Switching between strategies resembles a phase transition

Higher recombination rates occur in subtelomeric regions

Recombination patterns relate to speciation and genetic diversity

Abstract

We discuss two different ways of chromosomes' and genomes' evolution. Purifying selection dominates in large panmictic populations, where Mendelian law of independent gene assortment is valid. If the populations are small, recombination processes are not effective enough to ensure an independent assortment of linked genes and larger clusters of genes could be inherited as the genetic units. There are whole clusters of genes which tend to complement in such conditions instead of single pairs of alleles like in the case of purifying selection. Computer simulations have shown that switching in-between complementation and purification strategies has a character of a phase transition. This is also responsible for specific distribution of recombination events observed along eukaryotic chromosomes - higher recombination rate is observed in subtelomeric regions than in central parts of chromosomes - for sympatric speciation and probably for non-monotonous relation between reproduction potential and genetic distance between parents.