Determination of the population genetic structure of the invasive weed Ageratina adenophora using ISSR-PCR markers

A genetic analysis of nuclear DNA was performed by inter-simple sequence repeat-polymerase chain reaction (ISSR-PCR) technique on 32 populations of Ageratina adenophora, an invasive triploid weed in China. Among the 100 ISSR markers detected, 12 showed genetic variation both within and among the populations. Among the 446 amplified bands, 93.5% were found polymorphic. Most individuals (99%) displayed a unique ISSR fingerprint pattern, which yielded a high level of polymorphism (Po = 93.5%) and genetic diversity (Nei’s HT = 0.2354). The estimates of population variation, based on ISSR-PCR, were high, as measured by the analysis of molecular variance (AMOVA, FST = 0.3140), the Wright’s F-statistics (GST = 0.3453), and the Shannon’s information index (Hsp = 0.3716). AMOVA revealed 68.6% genetic variation within the populations and 91.2% within the provinces. The Mantel test showed that genetic distance was significantly correlated with geographic distance.