Fig. 3

The compositional changes in the transportomes of prokaryotes with different genome sizes. (a) Comparison between the transportome size and total gene number among prokaryotes including bacteria and archaea. All of the 126 studied species are clustered into three groups based on the total number of the genes. (b) The fraction of ATP-dependent transporters in the transportomes. (c) The fraction of secondary transporters in the transportomes. (d) The fraction of ion channels in the transportomes. The values on panels b-d are shown as mean +/− t-test based 99% confidence interval. The variations were also confirmed on the arc sin √x transformed data (See Additional file 2: Data S1). Group I and III differ significantly for all of the transporter classes with a p-value of < 0.001