Phylogenetic trees of the mixed sample (left panels) compared to the original inner-ring (upper right panel) and outer-ring (lower right panel) trees. Points are colour-coded according to their region of origin (purple: inner ring; orange: outer ring). In the right panels, coloured points highlight the particles selected to construct the mixed tree. Red lines indicate the members of the main clade in the original inner-ring tree. The central panels show the correspondence between the positions of the selected particles in the original trees and their rearrangement in the mixed tree.