Figure 3.

3-D plot for the vectorial profiling of each virus onto the three eigen-vectors. The tetra-nucleotide usage patterns V for the replicase open reading frame in each virus have been redisplayed on the 1^st, 2^nd and 3^rd eigen-vector axes ('o' represents positive strand ssRNA virus; x represents negative strand ssRNA virus). The two families of viruses clustered into two different regions of the plot.