Horizontal transmission and recombination maintain forever young bacterial symbiont genomes
Fig 3
Horizontal transmission and recombination introduce novel alleles into symbiont populations.
A) Model of endosymbiont genotype (pink vs. white) distributions under well-mixed high horizontal transmission rates and differentiated, low horizontal transmission rates. B) Horizontally transmitted mytilid (blue) and mixed mode transmitted solemyid (green) symbionts are well mixed among hosts, whereas the nearly strictly vertically transmitted vesicomyid symbionts (yellow) are highly differentiated among hosts. Error bars = 95% confidence intervals from non-parametric bootstrapping. C) Intrahost population folded allele frequency spectra (AFS) are shaped by access to gene flow, which is enabled by horizontal transmission and recombination. D) Recombination rates are significantly higher in the mytilid (blue) and solemyid (green) symbiont genomes compared to the vesicomyid symbiont genomes (yellow). Error bars = 95% confidence intervals.