Fig. 2: Time allows for genes to become more prevalent and spread more broadly.

A, B For each gene family, the time since initially reported in the scientific literature, a proxy for AR gene emergence, is plotted against the prevalence in human gut microbiomes (left) and number of genera in which the gene is found (right). Marker color/shape indicate the AR gene class. Two-sided Pearson’s ρ, p-value and R2 are reported. C Statistics (two-sided Pearson’s ρ, p-value and R2) are reported for the years since AR gene emergence and taxonomic spread computed at different taxonomic levels.