PMC

Frequency distribution of Q-values generated in structure for trees sampled in Alberta and British Columbia. The cutoff values used to delineate lodgepole pine and jack pine ancestry are indicated by the dashed vertical lines.

Ancestry plots generated in introgress for hybrid individuals for each microsatellite locus: dark green – lodgepole homozygotes; green – lodgepole/jack pine heterozygote; light green – jack pine homozygote and for the entire individual. (A) 100 hybrid individuals genotyped in Alberta; (B) Eighty simulated hybrid individuals generated from reference lodgepole pine and jack pine.

Jack pine (Pinus banksiana) and lodgepole pine (Pinus contorta) species ranges and sample locations in western North America. Range distributions for Pinus contorta and Pinus banksiana were obtained from USGS (http://esp.cr.usgs.gov/data/atlas/little/, accessed 29 July 2010) and are based on Little ().

Receiver operating characteristic (ROC) Curves for bootstrapped cross-validation tests of individual species logistic regression models. In these models, the response variable was a reclassified binary variable derived from the original continuous Q-values. ROC curves were plotted, and average area under the curve (AUC) was calculated for 100 cross-validation tests using 60% training and 40% testing data. A greater AUC indicates better model performance.

Species distribution for lodgepole and jack pine modeled by logistic regression (QValue ˜ Elev + CMI + MAP + SHM + EXT_Cold + Latitude + Longitude; see ). Color gradient represents the continuous predicted Qs from lodgepole pine (dark green) in the west, to jack pine (light green) in the east. Solid lines represent the 10th and 90th percentiles of the predicted Qs and indicate the revised ‘pure’ species boundaries according to our molecular criteria. The area between the black contours represents the revised, genetically determined pine hybrid zone. Also included are the historical eastern and western boundaries of the lodgepole and jack pine distributions, respectively (dashed lines), outlined by Little () for reference. Historical distribution data were obtained from USGS (http://esp.cr.usgs.gov/data/atlas/little/, accessed 29 July 2010).The spatial extent of prediction was determined by the extent of the climate data model (PPClimate v3.2).