Microsatellite DNA analysis of genetic effects of harvesting in old-growth eastern white pine (Pinus strobus) in Ontario, Canada.
Rajora, O. P.; Rahman, M. H.; Buchert, G. P.; Dancik, B. P.;
Molecular Ecology Year: 2000 Vol: 9 Issue: 3 Pages: 339-348 Ref: 35 ref.
2000
บทคัดย่อ
Microsatellite DNA markers from 13 simple sequence repeat (SSR) loci were used to compare genetic diversity between preharvest pristine and postharvest residual gene pools of two adjacent virgin, old-growth (approx equal to 250 years) stands of eastern white pine (Pinus strobus) in Ontario. There was concurrence in genetic diversity changes in the postharvest gene pools of the two stands. The total and mean numbers of alleles detected in each stand were reduced by approx equal to 26% after tree density reductions of approx equal to 75%. Approximately 18 and 21% of the low-frequency (0.25 > P more than or equal to 0.01) alleles and 76 and 92% of the rare (P < 0.01) alleles were lost from residual stands A and B, respectively, after harvesting. Multilocus gametic diversity was reduced by 38 and 85% and genotype additivity by approx equal to 50% in the residual stands after harvesting. Latent genetic potential of each stand was reduced by approx equal to 40%. Although heterozygosity was reduced (1-
5%) in the postharvest residual stands, the reductions were not substantial and not comparable to those using other genetic diversity measures. The reductions in genetic diversity measures were slightly higher than those theoretically expected in post-bottleneck populations according to drift theory. In the absence of substantial gene migration that could ameliorate the genetic losses, the ability of the postharvest white pine gene pools to adapt to changing environmental and disease conditions may have been compromised. The microsatellite DNA results for genetic effects of harvesting in old-growth eastern white pine stands were similar to those that reported earlier from allozyme analysis (Conservation Biology (1997) 11 747-758). The results indicate that silvicultural practices should ensure that the gene pools of remaining pristine old-growth stands are reconstituted in the regenerating stands.