PCR assessment for validation of the OSBRI1 ortholog-containing contigs representing two homoeologous genomes in switchgrass. Ethidium bromide-stained agarose gel showing PCR products amplified from DNAs of the six BAC clones assembled in the two contigs as shown in Figure 4. Primers designed for PCR amplification of DNA fragments (p1 to p12) as indicated in Figure 4 were listed in Additional file 1. A molecular weight ladder is shown on the left. Results of PCR amplification with 12 primer pairs for the 6 BAC clones were summarized in Table 3.