Fig. 3
Presence/absence survey of 22 mitochondrial chromosomes from 25 different populations of S. noctiflora (Table S1) and the close relative S. undulata. For each chromosome, presence/absence was assessed with three different PCR markers in each chromosome. Dark gray shading indicates positive detection for all three markers; medium gray shading indicates positive detection for two of three markers; light gray shading indicates positive detection for only one of three markers. For three chromosomes, the analysis was performed with only two markers (BRP41-OSR45, OSR58, and BRP57). In these cases, dark gray shading indicates detection of both markers. The chromosomes are divided into four categories as described in the Methods. Note that one of the “OSR-specific” chromosomes (OSR46) was found to be present at low levels in BRP and other samples from that group (see Results). This chromosome is recorded as present, but it is also possible that it has been lost from the mitochondria and only retained as a numt
