Supplemental online methods

Sequencing of Buchnera amino acid genes Amplification primers (table S2) were designed using the sequenced genome of Buchnera APS (NC_002528.1) and synthesized by Eurofins-MWG Operon. PCR conditions were an initial denaturing step at 94° C for 2 min, followed by 30 cycles of 94° C for 30 s, 54-60o C depending on primer Tm for 30 s, 72° C for 2-4 min depending on amplicon length, and a final extension of 10 min at 72° C. Products were visualized on 1% agarose gel in TBE stained with ethidium bromide, and amplicon sizes were determined using the Invitrogen 1kb plus DNA ladder. Products were extracted from the gel using the Qiaquick Gel Extraction kit (Qiagen). When necessary, PCR products were cloned using the pGEM T-Easy kit from Promega. Clones containing the inserts were selected by blue/white screening on LB agar plates with 100μg ampicillin, 0.5 mM IPTG and 80μg X-gal. White colonies were grown to log phase in LB media with 100μg/ml ampicillin and plasmids were extracted with the 5-Prime Fast Plasmid Mini-prep kit. Sequencing primers (table S2) were developed based on the published genome sequence of Buchnera APS and were placed every 400-500bp along the amplicon. Sequencing was performed by the University of Arizona Genetics Core in Tucson, AZ, USA by the dideoxy chain termination (Sanger) method on an ABI 3700XL. Sequences were manually edited and assembled in Sequencher 4.7 and compared to the reference sequence of Buchnera APS using BLAST.