Open reading frames were located using the ORF Finder tool at NCBI (http://www.ncbi.nlm.nih.gov/projects/gorf/) and by comparison with the genome annotations of PARV4 and partetraviruses. Prediction of transmembrane domains was performed using TMHMM version 2.0 server (http://www.cbs.dtu.dk/services/ TMHMM/) [26] . Functional annotation of predicted proteins was performed by BLAST similarity search against annotations in the NCBI RefSeq database, as well as by using the InterProScan search tool (http://www.ebi.ac.uk/Tools/pfa/iprscan/) [27] . Multiple alignments of sequences for phylogenetic analysis were constructed using MUSCLE version 3.8.31 [28] , and phylogenetic informative regions were extracted using BMGE [29] . Maximum-likelihood phylogenetic trees were constructed using PHYML version 3 [30] , under the best-fit protein evolution model as selected by ProtTest 3 [31] . Recombination detection was performed using bootscan analysis (as implemented in SimPlot) [32] and GARD [33] . Sites under positive selection were inferred by consensus between the single-likelihood ancestor counting (SLAC), fixed effects likelihood (FEL) and random effects likelihood (REL) methods as implemented on the DataMonkey server (http://www.datamonkey.org) [34] . A p-value of ,0.1 is considered to be statistically significant for the positive selection analysis.