Figure 3

Frequencies of microsatellites among the gene indices of 24 plants. The microsatellite frequencies are calculated in SSR counts per megabase nucleotide information (counts/Mbp) as detected in the gene indices of 24 phylogenetically well distributed plant species. The total SSR frequency is further subclassified into trimer, dimer and other SSRs. Other SSRs consist of tetramer, pentamer and hexamer SSRs (see also Additional file 1).