Pinus bungeana is a three-needle pine with typical fragmented distribution in central and northwestern China. Its natural resources are gradually decreasing and need to be conserved. For conserving genetic diversity o...Pinus bungeana is a three-needle pine with typical fragmented distribution in central and northwestern China. Its natural resources are gradually decreasing and need to be conserved. For conserving genetic diversity of P. bungeana, the authors sampled 10 natural populations in its distribution areas and conducted the analysis of isozymes. Thirty one loci with 53 alleles on the basis of 16 enzyme systems were assayed. The parameters of genetic diversity at species and population level are respectively as follows: As = 1.742, Ae[s] = 1.49, Ps = 54.8%, He[s] = 0.162, Ap = 1.39, Ae[p]= 1.30, Pp = 34.85, He[p] = 0.0986. In comparison with other pines, P. bungeana possesses a slightly low amount of genetic variation especially at the population level. By contrast, the level of population genetic differentiation (GST = 0.135) is higher compared to other pines. All ten populations are divided into three groups according to Nei抯 genetic identity (I). There is a slight relation (r = 0.31) between genetic distance and geographical distance. Some populations are obviously deviate from Hardy-Weinberg equilibrium but the total population is basically accordant with Hardy-Weinberg equilibrium. The correlation analysis between allele frequencies and ecological factors showed that the alleles at loci of Idh and Pgi-2 had gradient variation trends of their frequencies. The sample capturing curves?analysis indicated that the captured alleles increased when the number of sampled populations increased and 99% out of whole allele pool of ten populations would be captured when five populations were randomly selected. At last, the population genetic structure of P. bungeana and its conservation strategy were discussed.展开更多
A gel electrophoresis method was used to study the genetic diversity of 8 Quercus mongolica populations throughout its range in China. Eleven of 21 loci from 13 enzymes assayed were polymorphic. Q. mongolica maintaine...A gel electrophoresis method was used to study the genetic diversity of 8 Quercus mongolica populations throughout its range in China. Eleven of 21 loci from 13 enzymes assayed were polymorphic. Q. mongolica maintained low level of genetic variation compared with the average Quercus species. At the species level, the mean number of alleles per locus (A) was 1.905, the percentage of polymorphic loci (P) was 52.38%, the observed heterozygosity (Ho) was 0.092 and the expected heterozygosity (He) was 0.099. At the population level, the estimates were A =1.421, P =28.976%, Ho = 0.088, He =0.085. Genetic differentiation (Gst was high among populations, it was 0.107. According to the UPGMA cluster analysis based on the genetic distance, 4 populations located in northeast and 2 populations in southwest of the geographical distribution are classified into 2 subgroups, but there was no clear relationship between genetic distance and geographic distance among populations. The low level of genetic diversity of Q. mongolica might be related to the long-term exploitation as economic tree species in history are comparatively seriously disturbed and damaged by human beings, and most of the existing stands are secondary forests.展开更多
基金the "Tenth Five-year Plan" National Key Project in Science and Technology (Grant No.2001-13)
文摘Pinus bungeana is a three-needle pine with typical fragmented distribution in central and northwestern China. Its natural resources are gradually decreasing and need to be conserved. For conserving genetic diversity of P. bungeana, the authors sampled 10 natural populations in its distribution areas and conducted the analysis of isozymes. Thirty one loci with 53 alleles on the basis of 16 enzyme systems were assayed. The parameters of genetic diversity at species and population level are respectively as follows: As = 1.742, Ae[s] = 1.49, Ps = 54.8%, He[s] = 0.162, Ap = 1.39, Ae[p]= 1.30, Pp = 34.85, He[p] = 0.0986. In comparison with other pines, P. bungeana possesses a slightly low amount of genetic variation especially at the population level. By contrast, the level of population genetic differentiation (GST = 0.135) is higher compared to other pines. All ten populations are divided into three groups according to Nei抯 genetic identity (I). There is a slight relation (r = 0.31) between genetic distance and geographical distance. Some populations are obviously deviate from Hardy-Weinberg equilibrium but the total population is basically accordant with Hardy-Weinberg equilibrium. The correlation analysis between allele frequencies and ecological factors showed that the alleles at loci of Idh and Pgi-2 had gradient variation trends of their frequencies. The sample capturing curves?analysis indicated that the captured alleles increased when the number of sampled populations increased and 99% out of whole allele pool of ten populations would be captured when five populations were randomly selected. At last, the population genetic structure of P. bungeana and its conservation strategy were discussed.
文摘A gel electrophoresis method was used to study the genetic diversity of 8 Quercus mongolica populations throughout its range in China. Eleven of 21 loci from 13 enzymes assayed were polymorphic. Q. mongolica maintained low level of genetic variation compared with the average Quercus species. At the species level, the mean number of alleles per locus (A) was 1.905, the percentage of polymorphic loci (P) was 52.38%, the observed heterozygosity (Ho) was 0.092 and the expected heterozygosity (He) was 0.099. At the population level, the estimates were A =1.421, P =28.976%, Ho = 0.088, He =0.085. Genetic differentiation (Gst was high among populations, it was 0.107. According to the UPGMA cluster analysis based on the genetic distance, 4 populations located in northeast and 2 populations in southwest of the geographical distribution are classified into 2 subgroups, but there was no clear relationship between genetic distance and geographic distance among populations. The low level of genetic diversity of Q. mongolica might be related to the long-term exploitation as economic tree species in history are comparatively seriously disturbed and damaged by human beings, and most of the existing stands are secondary forests.
