Contradictory effects were seen in previous observations on the influence of the translation initiation rate on the frameshift efficiency. The frameshift efficiency of a plant virus, the beet western yellow virus (BWYV), was higher in a reticulocyte lysate than in a wheat germ extract, which has a lower rate of translation initiation (35) . Also, the frameshift efficiency of the human T-cell leukemia virus type II (HTLV-2), when measured in a reticulocyte lysate, was higher with capped than with uncapped mRNAs, which have a lower rate of translation initiation (36) . These observations disagree with our results that show a negative relationship between the rate of translation initiation and the frameshift efficiency. However, Paul et al. (37) , when comparing the frameshift efficiency of the barley yellow dwarf virus (BYDV) with capped and uncapped mRNAs in a yeast extract, found that increasing the translation initiation rate decreased the frameshift efficiency. Furthermore, Lopinski et al. (38) , who investigated in vivo the effect of a reduced translation initiation rate on the frameshift efficiency of the L-A virus of S. cerevisiae, found that this efficiency was increased under these conditions. The results of Paul et al. (37) and Lopinski et al.(38) are in perfect agreement with our findings, and, in line with them, we present the following model that explains our results ( Figure 6 ).