Analysis of the genetic stability of the rIBVs following passage at a low MOI.

<p>Replicates R1 of BeauR-hRlucΔ5ab, BeauR-IBVhRlucΔ5ab, BeauR-hRlucΔIR and BeauR-hRlucΔ3ab were passaged on CK cells from P4 to P12 at an MOI of 0.01. Extracellular virus was harvested 24 hpi and RNA analysed by RT-PCR in which the virus genomes were amplified using primers flanking the inserted reporter genes (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067875#pone-0067875-t002" target="_blank">Table 2</a>) and visualised by gel electrophoresis. Observation of expected PCR products representing genetically stable virus is indicated to the right by closed arrowheads. Genetic instability was observed for BeauR-hRlucΔIR and BeauR-hRlucΔ3ab as indicated by the appearance of smaller PCR products (open arrowheads) and represented deletions within reporter gene sequences. Size markers (L) in base pairs are indicated to the left.