Neutral Genetic Variation
Our dataset of 192 genotypes analyzed with ddRAD yielded 9195 SNP loci.
The 16 Arizona populations show strong differentiation with an average
pairwise FST = 0.175 and 95% confidence interval of
0.144-0.205. This result is consistent with the population structure
(FST = 0.221) found across populations collected
throughout the entire range of P. fremontii obtained with
microsatellite loci (Cushman et al. 2014). It is within the range
of other Populus species, from another strongly differentiated
species, P. angustifolia with a FST = 0.21 (Evanset al. 2014), to very low genetic structure (FST= 0.01) found in P. tremula (Hall et al. 2007).