Table 1. Distribution of subtomograms in the five different classes shown in Fig 1.

The length of the dsRNA densities as measured in the averages is stated, as well as their contribution to the total length of the genome. The sum indicates the total percentage of the genome that could be resolved in the subtomogram average classes. This number (52%) is smaller than the fraction of the genome initially traced (80%) since only the consensus structure appears in the subtomogram average. Number of particles refers to the total number of subtomograms, from 22 spherules.

Class	Length (nm)	Number of particles	Total length per spherule (bp)	% genome
1	32.3	171	1432	16.3
2	24.5	143	980	7.1
3	24.9	192	622	9.7
4	30	135	849	8.2
5	30.5	264	723	11.1
Sum	142.2	905	4606	52.4