Figure 1. Bacterial network of the human milk microbiome reconstructed using the data sets of Hunt et al.

(2011): Figure (1a) and (1b) show the two disconnected sub-networks (components) of the breast milk bacterial network; Figure (1c) and (1d) are the same components, corresponding to (1a) and (1b), respectively, assuming the Staphylococcus and Corynebacterium nodes were eliminated. The green line represents a positive correlation (cooperative interaction) while the red line represents a negative correlation (non-cooperative interaction). Obviously, when the two mutually cooperative players Staphylococcus and Corynebacterium are removed, the whole network becomes totally cooperative (Figure 1c & 1d).