Fig. 2: Developmental differences in gut microbial diversity and composition between infants at elevated- and low-likelihood of ASD.

a Infants at elevated-likelihood of ASD showed higher alpha diversity during the first year of life, but lower diversity thereafter compared to the low-likelihood group. Dots represent mean estimate per group and whiskers show standard errors. b At 5 months of age, the low-likelihood group presented more Bifidobacterium species (B. breve, B. Bifidum, B. Longum, and B. kashiwanohense), while the elevated-likelihood group harbored more Clostridium related species (C. clostridioforme, C. neonatale, C. difficile, and C. bolteae), B. producta, R. gnavus, and K. variicola. Positive effect sizes indicate higher abundance in the low-likelihood group, while negative effect sizes indicate a greater presence of the taxon in the elevated-likelihood group. Displayed OTUs have p < 0.05 and a circle stroke indicates if the adjusted p value was <0.25. c At 36 months of age, none of the OTUs had an adjusted p value < 0.25, but several species that were more abundant in the low-likelihood group (A. senegalensis, A, timonensis, and I. butyriciproducens), as well as different Bacteroides species that were more abundant in the elevated-likelihood group had absolute effect sizes >0.5. d At 5 months of age, infants at elevated-likelihood of ASD presented significantly less Bifidobacterium, and more Clostridioides and Clostridium compared to infants at low-likelihood of autism. e At 5 months of age, infants at elevated-likelihood of autism had a significantly lower Bifidobacterium/Clostridium ratio compared to the low likelihood one. Boxplots (d, e) represent first (lower), median and third (upper) quartile. Wilcoxon test: *p < 0.05, **p < 0.01. ELCS Early Learning Composite Scores, EL elevated-likelihood, LL low-likelihood.