To determine the nature of the recombinant RNAs derived from C1C2 T2B T3, the recombinant RNAs derived from this virus were purified from infected plants, subjected to RT-PCR and the RT-PCR products were then cloned into the pBluescript SK + vector for sequencing. The sequencing results from five independent clones showed that there was one type of RNA 3 recombinant derived from C1C2 T2B T3, containing 2370 nt, of which the 5 0 terminal 2060 nt was derived from the 5 0 terminal 2060 nt of TAV RNA 3 ( Figure 3A right, open bar), while the 3 0 terminal 310 nt was identical to the 3 0 terminal 310 nt of Q-CMV RNA 1 ( Figure 3A right, stippled bar). The crossover site on the TAV RNA 3 sequence was 7 nt 5 0 of a homologous sequence of 23 nt conserved in all three genomic RNAs, and 3 nt 5 0 of this conserved 23 nt sequence in the Q-CMV RNA 1 sequence.