Fig. 9
The numbers of genetic changes acquired by clones after 700 generations of evolution at pH 6.5 (strong nitrite [NO2−] toxicity, strong interdependence) sorted by the functional annotations of the target genes. The horizontal bars and P-values indicate statistically significant outcomes from two-sample Wilcoxon rank-sum tests. The stars indicate P-values less than 0.05. Data are presented as Tukey box plots. The numbers of genetic changes include synonymous and non-synonymous point mutations, insertions, deletions, and multiplications. Both the nitrite cross-feeding clones and the completely denitrifying clones acquired genetic changes that are unique to nitrite-cross-feeding or complete denitrification. Functional categories (COG): S, function unknown; N, cell motility; T, signal transduction; G, carbohydrate transport and metabolism; I, lipid transport and metabolism; C, energy production and conversion; P, inorganic ion transport and metabolism; K, transcription; E, amino acid transport and metabolism; H, coenzyme transport and metabolism; L, replication, recombination and repair; O, posttranslational modification, protein turnover, and chaperones; Q, secondary metabolites biosynthesis, transport and catabolism; V, defense mechanisms