Species most associated with Ethiopian, westernized (here, Italian and Swedish), and non-westernized (here, Tanzanian and Ghanaian) infants aged 0-12 years. Because of the different age distribution between non-westernized and westernized infants, we randomly picked westernized infants aged 0-6 months, 6-12 months, and 1-12 years to get a similar age distribution with respect to Ethiopian ones before performing a Wilcoxon test. The test was repeated 10 times with 10 different random pickings, with each test comparing the microbiome composition of 127 westernized and 20 Ethiopian infants (0-6 months: 55 West. and 12 Eth.; 6-12 months: 27 West. and 6 Eth.; 12-36 months: 9 West. and 2 Eth.). Non-westernized cohorts already had an age distribution similar to the Ethiopian one, so we performed a simple Wilcoxon test (28 non-West. and 26 Eth.). Reported here are the 20 species that showed the strongest association with Ethiopian, westernized, or non-westernized infants and that had >0.05% average relative abundance and >20% prevalence in at least one of the two compared categories. For a full list, seeData S1. The box plots show the first and third quartiles (boxes) and the median (middle line); the whiskers extend up to 1.5x the IQR.
