Temporal distribution of the samples from the multicenter pediatric allo-HSCT cohort analyzed in this study. Each point in the graph represents 1 of 180 fecal samples for the 90 patients included in this study, sampled before transplantation and at neutrophil engraftment. Samples are plotted based on the time relative to allo-HSCT (day 0) on the horizontal axis. The color code is based on alfa diversity as measured by the Shannon index.