Neighbour-Net tree of all NIF type domains detected in the model genomes. The coloured wedges indicate the distinct clusters defined by the Markov clustering algorithm. P. falciparum sequences appearing in the tree are labelled by capital letters: A, PFE0795c; B, PF07_0110; C, PF10_0124; D, MAL13P1.275. A high-resolution version of this Figure is available as a PNG file (see Additional file 10). We recommend viewing this file using a graphics programme enabling magnification, such as Microsoft Office Picture Manager.