Hierarchical genotype networks and incipient ecological speciation in Q$β$ phage quasispecies

Fuente: arXiv
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Hauptverfasser: Seoane, Luis F, Secaira-Morocho, Henry, Lázaro, Ester, Manrubia, Susanna
Format: Preprint
Veröffentlicht: 2024
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author Seoane, Luis F
Secaira-Morocho, Henry
Lázaro, Ester
Manrubia, Susanna
author_facet Seoane, Luis F
Secaira-Morocho, Henry
Lázaro, Ester
Manrubia, Susanna
contents Understanding how viral mutant spectra organize and explore genotype space is essential for unraveling the mechanisms driving evolution at the finest scale. Here we use deep-sequencing data of an amplicon in the A2 protein of the RNA bacteriophage Q$β$ to reconstruct genotype networks with tens of thousands of different haplotypes. The study of populations evolved under different temperature regimes uncovers generic topological features conditioned by fundamental structural motifs of genotype networks -- tetrahedrons, triangles, and squares -- that govern their local architecture. Mutant swarms display a hierarchical structure where sequences cluster around a highly connected and abundant sequence core that sustains population diversity. The immediate neighborhood of this core is comprehensively sampled, with no signs of selection, while a few mutations away sampling becomes dynamical and sparse, showing signs of purifying selection. By aggregating genotype networks from populations adapted to different temperatures, we capture the early stages of evolutionary divergence, with overlapping populations that remain connected through short mutational paths. Even at the time scale of these experiments, evolutionary pathways might be multiple, preventing the backward reconstruction of unique trajectories once mutations have been fixed. This analysis provides a detailed view of the local, fine-scale processes shaping viral quasispecies evolution and underscores the usefulness of genotype networks as an enlightening visualization of the organization of mutant swarms.
format Preprint
id arxiv_https___arxiv_org_abs_2411_07110
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Hierarchical genotype networks and incipient ecological speciation in Q$β$ phage quasispecies
Seoane, Luis F
Secaira-Morocho, Henry
Lázaro, Ester
Manrubia, Susanna
Populations and Evolution
Adaptation and Self-Organizing Systems
Biological Physics
Molecular Networks
Understanding how viral mutant spectra organize and explore genotype space is essential for unraveling the mechanisms driving evolution at the finest scale. Here we use deep-sequencing data of an amplicon in the A2 protein of the RNA bacteriophage Q$β$ to reconstruct genotype networks with tens of thousands of different haplotypes. The study of populations evolved under different temperature regimes uncovers generic topological features conditioned by fundamental structural motifs of genotype networks -- tetrahedrons, triangles, and squares -- that govern their local architecture. Mutant swarms display a hierarchical structure where sequences cluster around a highly connected and abundant sequence core that sustains population diversity. The immediate neighborhood of this core is comprehensively sampled, with no signs of selection, while a few mutations away sampling becomes dynamical and sparse, showing signs of purifying selection. By aggregating genotype networks from populations adapted to different temperatures, we capture the early stages of evolutionary divergence, with overlapping populations that remain connected through short mutational paths. Even at the time scale of these experiments, evolutionary pathways might be multiple, preventing the backward reconstruction of unique trajectories once mutations have been fixed. This analysis provides a detailed view of the local, fine-scale processes shaping viral quasispecies evolution and underscores the usefulness of genotype networks as an enlightening visualization of the organization of mutant swarms.
title Hierarchical genotype networks and incipient ecological speciation in Q$β$ phage quasispecies
topic Populations and Evolution
Adaptation and Self-Organizing Systems
Biological Physics
Molecular Networks
url https://arxiv.org/abs/2411.07110