Genetic variation among local populations of jack pine (Pinus banksiana)

Genetic variability in three jack pine (Pinus banksiana) populations, spaced 10 km apart in southern Manitoba, was analyzed electrophoretically for 15 enzymes encoded by 20 structural loci. These populations were studied as spatial and temporal controls in an investigation of the effects of long-term gamma irradiation on boreal tree species. Individual populations were, on average, polymorphic at 53.3% of the loci and had 2.0 alleles per locus. Individual trees were heterozygous at 20.7% of their loci. An F-statistic analysis revealed an overall 10% excess of heterozygotes over Hardy–Weinberg expectations. Only 2% of the genetic variation occurred among populations. Consequently Nei's genetic distance between populations was small . The amount and disposition of the genetic variation in neighbouring populations resembled that observed by others among widely spaced populations. The similarity of the genetic structure of jack pine populations at the meso- and macro-geographic levels might result from the an...