Fig. 1.

Distribution of genome sizes of ssRNA+ viruses. Box-and-whisker graphs were used to plot the family/group-specific distribution of genome sizes of all ssRNA+ viruses whose genome sequences have been placed in the NCBI Viral Genome Resource (Bao et al., 2004) by December 7, 2005 (Faase and Gorbalenya, unpublished data). Four major groups of nidoviruses are highlighted with the Nido- prefix, and the Coronaviridae family is split into the Nido-Coronavirus and the Nido-Torovirus groups. The box spans from the first to the third quartile and includes the median, indicated by the vertical line. The whiskers extend to the extreme values that are distant from the box at most 1.5 times the interquartile range. Values beyond this distance are indicated by circles (outliers).