STEM-LOOP RNA. “Quasispecies can also demonstrate group preclusion (e.g., hepatitis C). Stem-loop RNA domains are found in long terminal repeats (and viral RNA) and mediate viral regulation/identity. Thus, stem-loop RNAs may be ancestral regulators.”
http://onlinelibrary.wiley.com/doi/10.1111/nyas.12565/full