Please credit the greengenes paper as the source alignment: http://aem.asm.org/cgi/content/full/72/7/5069?view=long&pmid=16820507 Image was created using the NAST alignment of 236469 16S rRNA gene sequenes from greengenes. Tree was built with the software, fasttree. by Morgan Price then edited in Arb by Phil Hugenholtz.