Due to their relatively higher rate of mutation during replication, RNA viruses are evolving rapidly and this is the basis of their ubiquity and adaptability [20, 21] . In this study, it is shown that the EB4 gene sequence carried by the chimeric CGMMV was systemically removed during the infection process. The order of the removal of the transgene was speculated to be the 5 to 3 direction ( Figures  6 and 7) . This is further supported by the detection of two additional nucleotides together with the read-through sequence "CC-AAA-TAG" downstream from the CGMMV CP ORF. This report shows the temporal in-host truncation of the transgene from a chimeric virus in a natural host. Recent report has shown truncation occurring in transgenic plants expressing the same or similar transgenes as the chimeric virus [22] suggesting targeting by a resistance mechanism or competition with the parental virus as the mechanism involved. The exact mechanism of truncation of the transgene in our study is less clear as a previous study using the same vector and host with a different transgene did not exhibit the same instability [7] . The larger size of the EB4 peptide in comparison to the Hepatitis B epitope, however, suggests that the truncation mechanism or transgene recognition by the virus was size dependent.