Heterogenic sequences in invA gene demonstrated among Salmonella strains by BLAST. It is more intensive at the 5′- and 3-′ ends (A). Target regions (or amplicons) in invA gene used for detection of Salmonella by PCR from previous reports were indicated with dash lines. Numbers in the invA gene are nucleotide positions of the 5′- or 3-′ ends of the amplicons in PCR detection schemes (see references in Table 3), and numbers in parentheses represent amplicon length in bp in qPCR assays (B) and conventional PCR assays (C). Subjects in the figure are not in scale.