tailieunhanh - Báo cáo khoa học: "Macrogeographic and fine-scale genetic structure in a North American oak species, Quercus rubra"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Macrogeographic and fine-scale genetic structure in a North American oak species, Quercus rubra L. | 261s Ann Sci For 1993 50 Suppl 1 261S-270S Elsevier INRA Original article Macrogeographic and fine-scale genetic structure in a North American oak species Quercus rubra L VL Sork s Huang E Wiener Department of Biology University of Missouri-St Louis st Louis MO 63121-4499 USA Summary Northern red oak Quercus rubra L is a widely distributed forest-dominant tree in North America. In this paper we present the results of 2 studies examining macrogeographic and fine-scale genetic structure in the North American oak species Quercus rubra L. The first study used allo-zymes as genetic markers to examine the distribution of genetic variation within and among 10 widely distributed populations in midwestern USA. Our results revealed a high level of genetic variability within the species and a moderate level of genetic differentiation among 10 populations sampled Fst . In the second study we evaluated fine-scale genetic structure of northern red oak in a single forest site in Missouri USA. First we used F-statistics to determine whether subpopulations in adjacent microhabitats on the scale of 1 ha show genetic differentiation within a 4-ha plot. Our findings showed very low values of differentiation Fst . However we also used a statistical technique called spatial autocorrelation analysis to evaluate the spatial dispersion of alleles within a 4-ha mapped plot. These analyses revealed that genetic structure exists on a much smaller scale. Using 3 different algorithms we found that near-neighbors have significant spatial autocorrelation which suggests that family structure occurs within the study population. population genetic structure I genetic variation genetic differentiation isozymes spatial autocorrelation Quercus rubra Resume structure génétique du chêne rouge d Amerique à réchelle géographique et à celle du peuplement. Le chêne rouge d Amerique Q rubra L est une espèce très répandue en Amérique du Nord. Cette contribution présente les résultats d une analyse