Development and characterization of microsatellite loci in Ixeridium dentatum (Asteraceae, Lactuceae)

We isolated and characterized seven microsatellite loci for the perennial herb Ixeridium dentatum ssp. dentatum, an apomictic triploid distributed throughout the lowland areas of East Asia. The number of alleles ranged from two to seven in 32 screened individuals of I. dentatum ssp. dentatum from Japan. The observed and expected heterozygosities were 0.000-0.950 and 0.000-0.891, respectively, calculated using genotypes of 20 individuals of I. dentatum ssp. nipponicum. One locus (msid4) deviated significantly from Hardy-Weinberg equilibrium (P = 0.0001). These microsatellites were also tested for cross-amplification in 11 other taxa of Lactuceae, including five endangered taxa. These primers should be useful genetic tools not only for Ixeridium but also for other Lactuceae taxa.