General function of conserved and variable HGCs. The difference in functional annotations between conserved and variable HGCs. Conserved here defined as the quarter of HGCs with the lowest nucleotide diversity (red bars) and variable defined as the quarter of HGCs with the highest nucleotide diversity (blue bars). Each HGC has a functional profile. A functional profile consists of one or more functional categories. The bars represent the percentage of HGC profiles, which contain the functional category listed to the immediate left of the bars.