Emergence of clones in sexual populations

Abstract

In sexual population, recombination reshuffles genetic variation and produces novel combinations of existing alleles, while selection amplifies the fittest genotypes in the population. If recombination is more rapid than selection, populations consist of a diverse mixture of many genotypes, as is observed in many populations. In the opposite regime, which is realized for example in the facultatively sexual populations that outcross in only a fraction of reproductive cycles, selection can amplify individual genotypes into large clones. Such clones emerge when the fitness advantage of some of the genotypes is large enough that they grow to a significant fraction of the population despite being broken down by recombination. The occurrence of this "clonal condensation" depends, in addition to the outcrossing rate, on the heritability of fitness. Clonal condensation leads to a strong genetic heterogeneity of the population which is not adequately described by traditional population genetics measures, such as Linkage Disequilibrium. Here we point out the similarity between clonal condensation and the freezing transition in the Random Energy Model of spin glasses. Guided by this analogy we explicitly calculate the probability, Y, that two individuals are genetically identical as a function of the key parameters of the model. While Y is the analog of the spin-glass order parameter, it is also closely related to rate of coalescence in population genetics: Two individuals that are part of the same clone have a recent common ancestor.

revised version

References in corpus (4)

• The noisy edge of traveling waves
• Effect of selection on ancestry: an exactly soluble case and its phenomenological generalization
• Statistical Genetics and Evolution of Quantitative Traits
• Exact solution of a model of time-dependent evolutionary dynamics in a rugged fitness landscape

Cited by in corpus (11)

• Genetic draft, selective interference, and population genetics of rapid adaptation
• Evolution of molecular phenotypes under stabilizing selection
• Adaptive evolution of molecular phenotypes
• Multidimensional epistasis and the transitory advantage of sex
• Statistical Genetics in and out of Quasi-Linkage Equilibrium (Extended)
• Gaussian Closure Scheme in the Quasi-Linkage Equilibrium Regime of Evolving Genome Populations
• A model with Darwinian dynamics on a rugged landscape
• Two fitness inference schemes compared using allele frequencies from 1,068,391 sequences sampled in the UK during the COVID-19 pandemic
• Extending the applicability of Thermal Dynamics to Evolutionary Biology
• The rate of adaptation in large sexual populations with linear chromosomes
• Classification of SARS-CoV-2 Variants through The Epistatical Circos Plots with Convolutional Neural Networks