Figure 2.

Both intrauterine environmental and genetic factors shape gut microbial composition in neonates. DCDA-C and DCDA-D represent DC twins with birth weight concordance and birth weight discordance, respectively. MCDA-C and MCDA-D represent MC twins with birth weight concordance and birth weight discordance, respectively. MCDA-D-L and MCDA-D-S represent the larger twin and smaller twin, respectively, according to birth weight for each MCDA-D twin pair. (A) Quantifying the contribution of various factors to shaping the neonate gut microbiota using the ACE model, in which the total variance is partitioned into genetic (A), common environment (C), and unique environment (E) effects. The x-axis refers to gut microbes at the genus level, which are ranked based on their A values in the twin with birth weight concordance. The y-axis represents the proportion of genetic effects (red), common environment effects (blue), and specific environment effects (grey) for each genus. (B) The discriminatory genera identified between the DCDA-D and DCDA-C groups or between the MCDA-D and MCDA-C groups. The x-axis represents the relative abundance of discriminatory genera. Blue and red circles denote DCDA-D- or MCDA-D-decreased and DCDA-D- or MCDA-D-enriched genera, respectively. (C) Bacterial genera with significant differences among the MCDA-C, MCDA-D-L and MCDA-D-S groups (adjusted p<0.05). Genus abundance in each sample was normalised to 10⁴ reads. (D) Relative abundance of four species from metagenomic sequencing data among the MCDA-C, MCDA-D-L and MCDA-D-S groups. P values were determined by two-tailed Wilcoxon’s rank-sum test. DC, dichorionic; DCDA, dichorionic-diamniotic; MC, monochorionic; MCDA, monochorionic-diamniotic.