ISSR markers in five North American Sceptridium species

Relationships among North American Sceptridium (sensu Škoda) species are often difficult to assess because of few stable distinguishing characters and high intraspecific variability. We used ISSR-PCR to examine relationships among four samples of Holubiella, 24 samples representing four diploid North American Sceptridium species, and a Russian Sceptridium sample. Nine ISSR primers yielded 147 polymorphic loci. We generated three neighbor-joining dendrograms using a Jaccard, Nei & Li, or Dice coefficient. All three coefficients cluster based solely on the presence of bands and not the absence. ISSR data analyses across all three coefficients were consistent with published analyses of DNA sequence data in supporting Holubiella as sister to all Sceptridium species sampled. Sister group relationships among the four Sceptridium species were not consistent across all three neighbor-joining analyses, and bootstrap support was generally low. However, 26 of the 29 samples consistently cluste...