observed frequency vs expected frequency plot interpretation

Question

[biohacker_tobe]

I'm trying to understand the output of a plot that considers the observed frequency and expected frequency. More or less I've thought that plotting the observed values against the expected values will inspect the degree to which pairs deviate from their expected co-occurrence frequency.

Here we can observe that there all phylogenetic relationships do not exhibit any lower than expected co-occurrence. This pattern is the contrary for all functional GCFs pairs and some of those that are random, where many of these points tend to have a low expected co-occurrence level.

I don't know what else I can interpret or gain from having a plot like this?