stained with a dye that fluoresces in ultraviolet light, and 

 photographed . 



Total DNA was extracted from each leaf sample using a 

 modified CTAB method previously described (Brunsfeld et al. 

 1992) . Purified DNA was next quantified and diluted to a uniform 

 concentration (10 ng/ul) . One hundred and twenty 10-mer primers 

 of random sequence (Operon Technologies) were tested using a 

 subset of Cirsium DNA samples. 



RAPD products whose presence or absence was unambiguous were 

 scored. Population samples were scored from at least three 

 different amplification and electrophoretic runs, ensuring the 

 repeatability of RAPD products. Phenetic segregation of 

 populations based upon presence (1) and absence (0) of RAPD 

 markers was conducted using Principal component analysis (PCA) 

 (SAS Institute Inc., Gary, NC) . 



RESULTS 



Enzyme Electrophoresis 



Seven loci (AAT, APH, LAP, PGI, PGM, TPI-1, and TPI-2) were 

 resolved for 150 individuals from twelve Cirsium populations from 

 westcentral Montana. Data from five enzymes could not be used 

 because of inconsistent staining or uninterpretable banding 

 patterns. Data were sorted and analyzed two ways: by 

 population/locality, and by species. 



Population/Locality Analysis - For this analysis each 

 locality was considered a single biological population and the 

 tentative field identification of individuals was ignored. Table 

 2 identifies the names of the 12 populations or localities used 

 in this analysis. Table 3 lists allele frequencies and the 

 number of individuals sampled (N) at each locality. Sample sizes 

 are small for some populations because of poor enzyme activity in 

 many of the late season leaf samples. 



Levels of genetic variation differ considerably among the 12 

 populations sampled (Table 4 and Appendix 1) . Values of A ranged 

 from 1.1 to 1.6; P varied from 14.3 to 4 2.9 percent; and H^ 

 ranged from 0.006 to 0.110. Nei's (1978) unbiased genetic 

 identity values were calculated for pairwise comparisons of all 

 12 populations (Table 5) . 



