I want to construct a phylogenetic tree based on the STs of K. pneumoniae. Seven housekeeping genes (gapA, infB, mdh, pgi, phoE, rpoB, and tonB) were sequenced using Sanger sequencing, and the double-stranded DNA was assembled. I queried the sequences in the Institut Pasteur database to identify the STs. However, I am unsure whether I should construct separate trees for each gene or concatenate the seven genes into a single sequence for each isolate before drawing a tree (and how to do it). Thanks for your help.