Fig. 3: The schematics and results of the simulations estimating the effect of the traA diversity.

a Two myxobacterial strains depicted with different surface colors have different traA genotypes while their sitAI barcodes are the same. Major strain outnumbers minor strain in the initial population size. traA alleles of the major group could be either compatible, partially compatible, or incompatible with the minor group. b Horizontal gene transfer may transform randomly selected myxobacteria into aggressors which gained additional sitAI alleles. OME with the original cells (susceptibles) and aggressors results in damage of susceptibles. c The surface color represents the traA genotype and dark stripes are used to denote the aggressors. d The sitAI genotypes of susceptibles and aggressors. In this simulation, all functional sitAI alleles present in susceptibles are present in aggressors. Aggressors have sitAI alleles that are absent in susceptibles (Families 2 and 4). e In the absence of the transformation into aggressors, mutations in the traA alleles generating the traA-minor group have no significant effect with respect to the proportional fitness. Black, blue, and red markers represent the mean proportional fitness when traA-minor groups possess traA alleles that are compatible (control), partially compatible, and incompatible with those of traA-major groups, respectively. Error bars represent the sample standard deviation. Two nutrient environments were applied: stable nutrient conditions (solid error bars) and fluctuating nutrient conditions (dashed error bars, Supplementary Movie 6). Fluctuating nutrient conditions resulted in a reduction in overall fitness and inflation of variance. f Proportional fitness of traA minority when randomly selected myxobacteria in the population, regardless of the group types, transformed into the aggressors. As traA-minor groups are less likely to possess aggressors, OME insulation from the traA-major groups conferred a fitness advantage in traA-minor groups. Lines connecting the datasets represent statistical significance (alpha level = 0.001). g Same as (e) with fitness incorporating fruiting body formation. On the assumption that the number (rather than the proportion) of the traA-allele-sharing cells primarily affects the formation of the fruiting body, the traA minority with partially compatible or incompatible traA alleles exhibits significantly lower fitness than the traA majority. h Same as (g) with aggressor invasion. i Explanations of the diagrams used in this figure.