MOLECULAR MEMORY. “There are additional observations that support the view that mutant spectra are true actors of evolutionary outcomes. Viral quasispecies can be endowed with a molecular memory consisting of minority genomes present at higher than basal frequency levels because the genomes had been dominant in a prior phase of evolution of the same lineage.”
http://www.sciencedirect.com/science/article/pii/S0042682215001580