Figure 2 Genes flux analysis and functional classification of niche specifying genes. A. Loss and gain of gene families (blue, gain; red, loss) in gene content since the last common ancestor (numbers in black). The size of the pie chart reflects the amplitude of total gene flux (gain + loss). B. COG functional classification of genes lost in the Apibacter genome. See Dataset S2 for complete list of gene families with annotations and COG category abbreviations. C. Venn diagram shows gene family distribution among the three major groups:Apibacter group, Clade C and Clade E.