I am performing phylogenetic analyses using 7 different fragments for the same set of individuals (all same species). By comparing the single-locus tree visually, no any two trees have identical topologies. PHT test by PAUP showed no significant difference among the first 6 fragments, but significant difference (P=0.001) between the 7th fragment and each of the first 6 fragments. I prefer to use the combined data set of all 7 fragments because all my individuals are belong to the same fungal species. But does anyone know a good reason for adding the 7th fragment (I need a reason when writing my paper), or any other test I can do? Thanks.