Figure 1. Explanatory variables of global variability of the 16S rRNA gut microbiota among 69 West African children of varying nutritional status.

(a) A Pearson Principal component analysis (PCA) of the 16S rRNA gut metagenomes of 69 West African children revealed that geography was the main factor in gut microbiota variability, as only recruiting centers differentiated children into distinct groups (up). (b) In a sensitivity analysis to test the robustness of the results, a second PCA was performed excluding 10 outliers (6 healthy children and 2 children with SAM from Dakar, Senegal, and 2 children with SAM from Niamey, Niger) identified by the ROUT method (Q = 1%) based on the Euclidian distance to the framework origin²⁴. This second PCA confirmed geography as the major determinant of the global variability of the gut microbiota among our samples (down). City: blue: Dakar (Senegal), green: Dielmo and N’Diop (contiguous villages in Senegal), red: Niamey (Niger). Age: red: up to 12 months, blue: >12 months and up to 24 months, green: >24 months, grey: missing data, Sex: red: female, blue: male, Nutritional status: green: healthy controls, red: severe acute malnutrition, blue: children with other forms of malnutrition.