Species distribution in MDR families. The species distribution in the individual families is shown using a gradient from white to dark blue (0% to 100% of the family). The columns represent the species groups A - archaea, B - bacteria, Pla - plants, Inv - invertebrates, Ver - vertebrates, Mam - mammals, Rod - rodents, Pri - primates. The families are ordered according to the MDR family enumeration. The numerical values underlying this figure are available in Additional file 5: mdr-distribution.