We used sequences of mitochondrial control region （807bp） in 75 samples from three breeding colonies and one wintering population to investigate the genetic diversity and population structure of Marsh Grassbird （Lo...We used sequences of mitochondrial control region （807bp） in 75 samples from three breeding colonies and one wintering population to investigate the genetic diversity and population structure of Marsh Grassbird （Locustella pryeri sinensis） in different regions of China. Marsh Grassbird retained a moderate amount of haplotype （0.759 ± 0.056） and nucleotide diversity （0.002）. The results of FST among 3 phy-logeographic units and ФST between breeding and wintering sites revealed little evidence of genetic distinction between different colonies. Neither UPGMA tree structure analysis nor Network picture analysis showed obvious divergence between populations at different locations. Analysis of molecular variance also showed a lack of regional subdivision within Locustella pryeri sinesis, 98.5% of source of variation within populations and only 1.5% among populations. The neutrality test showed negative Fu’s FS value, which, in combination with detection of the mismatch distribution, suggested that population expansion occurred in the evolu-tionary history of this species. This hypothesis was further supported by Tajima’s D test and Fu’s test （D = -1.80, p = 0.02; Fs = -22.11, p = 0.001）, this expansion was estimated to occur about 28,700 years ago.展开更多
Hybrid zone is a very critical concept within the evolutionary biology, because it would offer us a better insight to understand the evolutionary role of gene flow and hybridization based on the cline model. This mini...Hybrid zone is a very critical concept within the evolutionary biology, because it would offer us a better insight to understand the evolutionary role of gene flow and hybridization based on the cline model. This minireview presents an expatiation of history perspectives and research developments upon basic concepts including hybrid zones, hybridization, hybrid and its the genetic cline model. Moreover, by figuring out the existing problem around the hybrids within conservative theory and practices, it suggests that the theory of hybrid zone be introduced into conservation biology and it would be provide a broader and more open theoretical background for conservative research and practices.展开更多
Forest management may have significant effects on forest connectivity and natural population sizes.Harvesting old-growth single trees may also change natural patterns of genetic variation and spatial genetic structure...Forest management may have significant effects on forest connectivity and natural population sizes.Harvesting old-growth single trees may also change natural patterns of genetic variation and spatial genetic structure.This study evaluated the impacts of forest management using a silvicultural system of seed trees on the genetic diversity and spatial genetic structure of Eremanthus erythropappus(DC.)MacLeish.A complete survey of 275 trees on four plots was undertaken out to compare the genetic variation of a managed stand with an unmanaged stand.We genotyped all adult and juvenile individuals 60 months after the management and compared the genetic diversity and the spatial genetic structure parameters.Genetic diversity was considered high because of an efficient gene flow between stands.There were no genetic differences between stands and no evidence of inbreeding.Genetic clustering identified a single population(K=1),indicating no genetic differentiation between managed and unmanaged stands.Adult and juvenile individuals of the unmanaged stand were more geographically structured than individuals from the managed one.There was a tendency of coancestry among juveniles at the first class of distance of the managed stand,suggesting a drift of genetic structure possibly caused by management.Understanding early responses to management on genetic diversity and stand structure is a first step to ensuring the effectiveness of conservation practices of tree species.The sustainability of forest management of E.erythropappus on genetic diversity,and more accurately,on spatial genetic structure needs evaluation over time to promote effective conservation of the population size and genetic variability.展开更多
Population connectivity through seed and pollen dispersal determines the genetic diversity,adaptive potential,and demography of plant metapopulations.In wind-pollinated trees,population connectivity is typically maint...Population connectivity through seed and pollen dispersal determines the genetic diversity,adaptive potential,and demography of plant metapopulations.In wind-pollinated trees,population connectivity is typically maintained by long-distance pollen flow,counteracting the genetic differentiation generated by drift and restricted seed dispersal.Although strong population fragmentation is theoretically expected to disrupt connectivity in forest trees,empirical evidence remains scarce and inconclusive.We investigated contemporary connectivity within a network of small remnant populations of a declining conifer(Taxus baccata L.),which have been hypothesized to be largely isolated from each other.We tested this hypothesis using molecular data for adult trees and naturally recruited seedlings from all known remnants across a fragmented landscape spanning a length of 20 km,and a specifically designed statistical approach to quantify contemporary pollen and seed migration rates between populations.We additionally assessed dispersal potential using a spatially explicit parentage analysis to estimate seed and pollen dispersal kernels within one of the remnants.Estimated pairwise migration rates between populations were barely detectable for seeds,while they were larger(up to 1.1%)and significant for pollen.Both seed and pollen migration rates decreased with geographic distance between populations,more steeply in the case of pollen migration.According to parentage-based dispersal kernels,51.8% of seeds and 11.4% of pollen travel less than 25 m,whereas 0.2% of seeds and 36.1%of pollen travel more than 250 m from a source tree.In addition,1.2% of pollen can travel more than 2.5 km.We showed that strong present-day population fragmentation,with separation distances over a few kilometers between small fragments,can substantially limit the connectivity of a wind-pollinated declining tree,leading to low pollen-mediated contemporary gene flow and null or virtually null demographic connectivity via seed dispersal.展开更多
放牧对草地植物种群遗传与进化产生重要影响，本研究利用 SSR 分子标记对4个不同放牧强度下垂穗披碱草种群遗传多样性进行研究，试验地选择在甘肃省甘南自治州玛曲县的阿孜试验站，利用8对多态性强的 SSR 引物对不同放牧压力下4个居群的...放牧对草地植物种群遗传与进化产生重要影响，本研究利用 SSR 分子标记对4个不同放牧强度下垂穗披碱草种群遗传多样性进行研究，试验地选择在甘肃省甘南自治州玛曲县的阿孜试验站，利用8对多态性强的 SSR 引物对不同放牧压力下4个居群的800个个体基因组进行检测，每个位点的有效等位基因数在1．2267～1．9976之间。利用 popgene 分析发现不放牧垂穗披碱草种群遗传多样性最高，在3种不同放牧地，中等放牧强度的遗传多样性指数较高，其次为重牧，最后为轻度放牧。在不同放牧干扰下的4个垂穗披碱草种群的遗传分化系数为0．5168，基因流 Nm ＝0．2337，说明4个种群的遗传变异主要发生在种群之间。从种质资源保护角度来讲，不放牧对于垂穗披碱草种质资源的保护是有利的；从草地利用角度，中等放牧强度比较合理。展开更多
基金supported by National Natural Science Foundation of China (No. 130370221 and No. 30770309)
文摘We used sequences of mitochondrial control region （807bp） in 75 samples from three breeding colonies and one wintering population to investigate the genetic diversity and population structure of Marsh Grassbird （Locustella pryeri sinensis） in different regions of China. Marsh Grassbird retained a moderate amount of haplotype （0.759 ± 0.056） and nucleotide diversity （0.002）. The results of FST among 3 phy-logeographic units and ФST between breeding and wintering sites revealed little evidence of genetic distinction between different colonies. Neither UPGMA tree structure analysis nor Network picture analysis showed obvious divergence between populations at different locations. Analysis of molecular variance also showed a lack of regional subdivision within Locustella pryeri sinesis, 98.5% of source of variation within populations and only 1.5% among populations. The neutrality test showed negative Fu’s FS value, which, in combination with detection of the mismatch distribution, suggested that population expansion occurred in the evolu-tionary history of this species. This hypothesis was further supported by Tajima’s D test and Fu’s test （D = -1.80, p = 0.02; Fs = -22.11, p = 0.001）, this expansion was estimated to occur about 28,700 years ago.
文摘Hybrid zone is a very critical concept within the evolutionary biology, because it would offer us a better insight to understand the evolutionary role of gene flow and hybridization based on the cline model. This minireview presents an expatiation of history perspectives and research developments upon basic concepts including hybrid zones, hybridization, hybrid and its the genetic cline model. Moreover, by figuring out the existing problem around the hybrids within conservative theory and practices, it suggests that the theory of hybrid zone be introduced into conservation biology and it would be provide a broader and more open theoretical background for conservative research and practices.
基金supported by the Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG)[CRA APQ-02641-14]in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-Brasil(CAPES)-Finance Code 001。
文摘Forest management may have significant effects on forest connectivity and natural population sizes.Harvesting old-growth single trees may also change natural patterns of genetic variation and spatial genetic structure.This study evaluated the impacts of forest management using a silvicultural system of seed trees on the genetic diversity and spatial genetic structure of Eremanthus erythropappus(DC.)MacLeish.A complete survey of 275 trees on four plots was undertaken out to compare the genetic variation of a managed stand with an unmanaged stand.We genotyped all adult and juvenile individuals 60 months after the management and compared the genetic diversity and the spatial genetic structure parameters.Genetic diversity was considered high because of an efficient gene flow between stands.There were no genetic differences between stands and no evidence of inbreeding.Genetic clustering identified a single population(K=1),indicating no genetic differentiation between managed and unmanaged stands.Adult and juvenile individuals of the unmanaged stand were more geographically structured than individuals from the managed one.There was a tendency of coancestry among juveniles at the first class of distance of the managed stand,suggesting a drift of genetic structure possibly caused by management.Understanding early responses to management on genetic diversity and stand structure is a first step to ensuring the effectiveness of conservation practices of tree species.The sustainability of forest management of E.erythropappus on genetic diversity,and more accurately,on spatial genetic structure needs evaluation over time to promote effective conservation of the population size and genetic variability.
基金supported by the National Science Centre,Poland(the grant UMO-2018/31/B/NZ8/01808 to IJC).
文摘Population connectivity through seed and pollen dispersal determines the genetic diversity,adaptive potential,and demography of plant metapopulations.In wind-pollinated trees,population connectivity is typically maintained by long-distance pollen flow,counteracting the genetic differentiation generated by drift and restricted seed dispersal.Although strong population fragmentation is theoretically expected to disrupt connectivity in forest trees,empirical evidence remains scarce and inconclusive.We investigated contemporary connectivity within a network of small remnant populations of a declining conifer(Taxus baccata L.),which have been hypothesized to be largely isolated from each other.We tested this hypothesis using molecular data for adult trees and naturally recruited seedlings from all known remnants across a fragmented landscape spanning a length of 20 km,and a specifically designed statistical approach to quantify contemporary pollen and seed migration rates between populations.We additionally assessed dispersal potential using a spatially explicit parentage analysis to estimate seed and pollen dispersal kernels within one of the remnants.Estimated pairwise migration rates between populations were barely detectable for seeds,while they were larger(up to 1.1%)and significant for pollen.Both seed and pollen migration rates decreased with geographic distance between populations,more steeply in the case of pollen migration.According to parentage-based dispersal kernels,51.8% of seeds and 11.4% of pollen travel less than 25 m,whereas 0.2% of seeds and 36.1%of pollen travel more than 250 m from a source tree.In addition,1.2% of pollen can travel more than 2.5 km.We showed that strong present-day population fragmentation,with separation distances over a few kilometers between small fragments,can substantially limit the connectivity of a wind-pollinated declining tree,leading to low pollen-mediated contemporary gene flow and null or virtually null demographic connectivity via seed dispersal.
文摘放牧对草地植物种群遗传与进化产生重要影响，本研究利用 SSR 分子标记对4个不同放牧强度下垂穗披碱草种群遗传多样性进行研究，试验地选择在甘肃省甘南自治州玛曲县的阿孜试验站，利用8对多态性强的 SSR 引物对不同放牧压力下4个居群的800个个体基因组进行检测，每个位点的有效等位基因数在1．2267～1．9976之间。利用 popgene 分析发现不放牧垂穗披碱草种群遗传多样性最高，在3种不同放牧地，中等放牧强度的遗传多样性指数较高，其次为重牧，最后为轻度放牧。在不同放牧干扰下的4个垂穗披碱草种群的遗传分化系数为0．5168，基因流 Nm ＝0．2337，说明4个种群的遗传变异主要发生在种群之间。从种质资源保护角度来讲，不放牧对于垂穗披碱草种质资源的保护是有利的；从草地利用角度，中等放牧强度比较合理。
