Functional category comparison of open reading frames within human milk versus infants’ and mothers’ feces. The percent of ORFs assigned to each functional category of genes is shown. Using the “Hierarchical Classification” tool within MG-RAST, ORFs within each metagenome were assigned to a functional category (maximum e-value of 1x10-5, minimum identity of 60%, and minimum alignment length of 15 aa). Asterisk denotes that the proportion of ORFs within the category is significantly different from that in human milk (Student’s t-test, P < 0.05). Breast-fed and formula-fed infant feces values are an average of five individuals, and mothers’ feces values are an average of three individuals. All subjects were unrelated.