Identifying putative novel overlapping elements in bluetongue virus. (A) FRESCo recovers a previously identified overlapping ORF in the VP6 gene as a pronounced region of excess synonymous constraint. (B) For each segment of the bluetongue virus genome, we show with red bars positions with SCEs at a 10-codon resolution. As in rotavirus, SCEs are concentrated near the 5’ and 3’ ends of genome segments. (C) A conserved ORF in NS3 corresponds to a strong signal of excess synonymous constraint. (D) The region also has a weak signal for a conserved RNA structure, suggesting an alternative possible function for the SCE.