However , the exceptional evolutionary plasticity of RNA viruses threatens the durability of the resistance
It has recently been shown that viral populations <*> may already contain enough genetic variability in the target sequence
However , the exceptional evolutionary plasticity of RNA viruses threatens the durability of the resistance conferred by these amiRs .
It has recently been shown that viral populations not experiencing strong selective pressure from an antiviral amiR may already contain enough genetic variability in the target sequence to escape plant resistance in an almost deterministic manner .