Figure 7

Coding potential statistics for the Group 3c coronavirus NS6 CDS and the overlapping ORFX. (1) Map of the NS6 CDS of BuCoV [GenBank: FJ376620], showing the proposed new coding sequence, ORFX, overlapping the NS6 CDS in the +1 reading frame. (2-5) Coding potential statistics based on an alignment of five Group 3c coronavirus sequences (see Figure 8 for accession numbers). (2-4) Positions of stop codons in each of the three forward reading frames. Note the conserved absence of stop codons in the +1 frame within the ORFX region. (5) MLOGD statistics for NS6 relative to a non-coding null model. (6) MLOGD statistics for ORFX (see Figure 3 for details). The predominantly positive scores indicate that ORFX is likely to be a coding sequence, but is subject to significantly weaker purifying selection than NS6. The negative scores at the 3' end of ORFX indicate that the C-terminal region of the putative product is not subject to strong functional constraints.