The identification and understanding of cryptic intraspecific evolutionary units(lineages) are crucial for planning effective conservation strategies aimed at preserving genetic diversity in endangered species.However...The identification and understanding of cryptic intraspecific evolutionary units(lineages) are crucial for planning effective conservation strategies aimed at preserving genetic diversity in endangered species.However, the factors driving the evolution and maintenance of these intraspecific lineages in most endangered species remain poorly understood. In this study, we conducted resequencing of 77 individuals from 22 natural populations of Davidia involucrata, a “living fossil” dove tree endemic to central and southwest China. Our analysis revealed the presence of three distinct local lineages within this endangered species, which emerged approximately 3.09 and 0.32 million years ago. These divergence events align well with the geographic and climatic oscillations that occurred across the distributional range.Additionally, we observed frequent hybridization events between the three lineages, resulting in the formation of hybrid populations in their adjacent as well as disjunct regions. These hybridizations likely arose from climate-driven population expansion and/or long-distance gene flow. Furthermore, we identified numerous environment-correlated gene variants across the total and many other genes that exhibited signals of positive evolution during the maintenance of two major local lineages. Our findings shed light on the highly dynamic evolution underlying the remarkably similar phenotype of this endangered species. Importantly, these results not only provide guidance for the development of conservation plans but also enhance our understanding of evolutionary past for this and other endangered species with similar histories.展开更多
After many unsuccessful attempts to obtain biologically active mRNAs from dry seeds of Davidia involucrata using available protocols,an effective procedure modified from Vicient and Delseny (1999) is developed.This me...After many unsuccessful attempts to obtain biologically active mRNAs from dry seeds of Davidia involucrata using available protocols,an effective procedure modified from Vicient and Delseny (1999) is developed.This method is based on the use of 8mol/L LiCl in the extraction buffer followed by phenol extractions.The differences with respect to the original method are the inclusions of 2% soluble PVP (10000Da) and 10 mmol/L cysteine in the extraction buffer to avoid oxidation of polyphenolics,the reduction in the number of phenol extractions,freezing the seeds for 10 minutes instead of using quarts.The author modifications conquer the perishing oxidation of polyphenolics,in their oxidized forms,polyphenols can covalently bind to proteins and nucleic acids; and permit the recovery of and an average of 240 μg total RNA per g of the seeds that is suitable for translation in vitro,northern hybridizations,and the construction of cDNA libraries.展开更多
Davidia involucrata is a rare endangered species belonging to the paleo-tropical flora of the Tertiary period, endemic to China, and has an important protection and ornamental value. However, the natural populations a...Davidia involucrata is a rare endangered species belonging to the paleo-tropical flora of the Tertiary period, endemic to China, and has an important protection and ornamental value. However, the natural populations and distribution areas of this ancient plant have been decreased sharply, because it suffers much disturbance from human activity in many regions. In this paper, data on Davidia involucrata forest in its most natural distribution areas were collected;the percentages of geographical areal types of seed-plant genera (Sensu Wu 1991) were summed;the community types were summarized using Braun-Blanquet methodology;and the geographical differentiation among communities was analyzed by detrended canonical correspondence analysis. The analysis of geographical types shows that temperate species are dominant and that tropical species also make up a high percentage. This indicates that Davidia involucrata forest is mainly temperate vegetation. In total, 16 communities were recognized by classification, and these communities were usually dominated by deciduous broad-leaved species, sometimes mixed with some evergreen species. The shrub layer of Davidia involucrata forest is generally occupied by bamboos. The geographical patterns among the communities are influenced mainly by temperature and moisture availability, and the forest is most likely to grow in warm, humid habitats.展开更多
In order to estimate the most effect stage and process on population growth and effective conserve the rare endangered plant Davidia involucrata, we analyzed the dynamics and the contributions of life-history componen...In order to estimate the most effect stage and process on population growth and effective conserve the rare endangered plant Davidia involucrata, we analyzed the dynamics and the contributions of life-history components on population dynamics based on Lefkovitch matrix model and sensitivity analysis. The life cycle of Davidia involucrata was divided into six stages (seed, seedling, juvenile, immature, early adult and late adult) based on the species characteristics and published literature data, the survival rates in each life-history stage were simulated using a static life table, and the fecundity of each stage was determined according to sample information. The results showed that the structure of the observed population was not ideal, and the numbers of seedlings and coppice shoots was similar. The population growth rate was influenced largely by individual growth process, and asexual reproduction made a larger contribution to population growth than sexual reproduction. However, sexual reproduction was more important than asexual reproduction, because most asexual reproducing individuals (the coppice shoots) were derived mainly from human destruction (e.g. felling trees). The most important stage was stage V (late adult), associated with seed production and germination. Therefore, conservation of Davidia involucrata populations should focus on stage V and sexual reproduction, in order to improve the seed production and germination rate, and to promote population stability and development.展开更多
基金supported by the Second Tibetan Plateau Scientific Expedition and Research program (No. 2019QZKK0502)Strategic Priority Research Program of Chinese Academy of Sciences (No. XDB31010300)+1 种基金Fundamental Research Funds for the Central UniversitiesInternational Collaboration 111 Program (BP0719040)。
文摘The identification and understanding of cryptic intraspecific evolutionary units(lineages) are crucial for planning effective conservation strategies aimed at preserving genetic diversity in endangered species.However, the factors driving the evolution and maintenance of these intraspecific lineages in most endangered species remain poorly understood. In this study, we conducted resequencing of 77 individuals from 22 natural populations of Davidia involucrata, a “living fossil” dove tree endemic to central and southwest China. Our analysis revealed the presence of three distinct local lineages within this endangered species, which emerged approximately 3.09 and 0.32 million years ago. These divergence events align well with the geographic and climatic oscillations that occurred across the distributional range.Additionally, we observed frequent hybridization events between the three lineages, resulting in the formation of hybrid populations in their adjacent as well as disjunct regions. These hybridizations likely arose from climate-driven population expansion and/or long-distance gene flow. Furthermore, we identified numerous environment-correlated gene variants across the total and many other genes that exhibited signals of positive evolution during the maintenance of two major local lineages. Our findings shed light on the highly dynamic evolution underlying the remarkably similar phenotype of this endangered species. Importantly, these results not only provide guidance for the development of conservation plans but also enhance our understanding of evolutionary past for this and other endangered species with similar histories.
文摘After many unsuccessful attempts to obtain biologically active mRNAs from dry seeds of Davidia involucrata using available protocols,an effective procedure modified from Vicient and Delseny (1999) is developed.This method is based on the use of 8mol/L LiCl in the extraction buffer followed by phenol extractions.The differences with respect to the original method are the inclusions of 2% soluble PVP (10000Da) and 10 mmol/L cysteine in the extraction buffer to avoid oxidation of polyphenolics,the reduction in the number of phenol extractions,freezing the seeds for 10 minutes instead of using quarts.The author modifications conquer the perishing oxidation of polyphenolics,in their oxidized forms,polyphenols can covalently bind to proteins and nucleic acids; and permit the recovery of and an average of 240 μg total RNA per g of the seeds that is suitable for translation in vitro,northern hybridizations,and the construction of cDNA libraries.
文摘Davidia involucrata is a rare endangered species belonging to the paleo-tropical flora of the Tertiary period, endemic to China, and has an important protection and ornamental value. However, the natural populations and distribution areas of this ancient plant have been decreased sharply, because it suffers much disturbance from human activity in many regions. In this paper, data on Davidia involucrata forest in its most natural distribution areas were collected;the percentages of geographical areal types of seed-plant genera (Sensu Wu 1991) were summed;the community types were summarized using Braun-Blanquet methodology;and the geographical differentiation among communities was analyzed by detrended canonical correspondence analysis. The analysis of geographical types shows that temperate species are dominant and that tropical species also make up a high percentage. This indicates that Davidia involucrata forest is mainly temperate vegetation. In total, 16 communities were recognized by classification, and these communities were usually dominated by deciduous broad-leaved species, sometimes mixed with some evergreen species. The shrub layer of Davidia involucrata forest is generally occupied by bamboos. The geographical patterns among the communities are influenced mainly by temperature and moisture availability, and the forest is most likely to grow in warm, humid habitats.
文摘In order to estimate the most effect stage and process on population growth and effective conserve the rare endangered plant Davidia involucrata, we analyzed the dynamics and the contributions of life-history components on population dynamics based on Lefkovitch matrix model and sensitivity analysis. The life cycle of Davidia involucrata was divided into six stages (seed, seedling, juvenile, immature, early adult and late adult) based on the species characteristics and published literature data, the survival rates in each life-history stage were simulated using a static life table, and the fecundity of each stage was determined according to sample information. The results showed that the structure of the observed population was not ideal, and the numbers of seedlings and coppice shoots was similar. The population growth rate was influenced largely by individual growth process, and asexual reproduction made a larger contribution to population growth than sexual reproduction. However, sexual reproduction was more important than asexual reproduction, because most asexual reproducing individuals (the coppice shoots) were derived mainly from human destruction (e.g. felling trees). The most important stage was stage V (late adult), associated with seed production and germination. Therefore, conservation of Davidia involucrata populations should focus on stage V and sexual reproduction, in order to improve the seed production and germination rate, and to promote population stability and development.
