| My general objective was to assess the nature and extent of genetic diversity within and among thirteen populations of the native North American dioecious tree, Gleditsia triacanthos located in northern, southern, western and central portions of the species' range of distribution using leaf tissue samples collected from all populations. I investigated genetic diversity using Random Amplification of Polymorphic DNA. To measure genetic differentiation I used several statistics, including Shannon's index of diversity, Wright's fixation index, Nei's genetic distance, and indirect gene flow. To compare samples I used Analysis of Molecular Variance.;Results indicate a high percentage of polymorphic loci per population. Relatively high levels of variation are evident within populations, but low levels among populations. Results of regional comparisons indicate higher levels of genetic variation within regions than among regions. In periphery, higher levels of gene flow and less genetic differentiation are present compared with the center of the range. No specific bands are found to distinguish categorically between female and male individuals. Results assessing the patterns of genetic variation among thorned and thornless individuals show no significant differences between groups. |
