Using RAPD technique, the DNA diversity of Cephalotaxus mannii Hook. f., its genetic diversity pattern, the reasons for its endangered position and conservative approaches were studied. The results show that: 1. The...Using RAPD technique, the DNA diversity of Cephalotaxus mannii Hook. f., its genetic diversity pattern, the reasons for its endangered position and conservative approaches were studied. The results show that: 1. The genetic diversity of C. mannii collected from five localities in Hainan is low, and its adaptability to environmental change is weak. 2. The differences of genetic diversity between intra- and inter-populations are great, and the major variation distributes within the population (DNA diversity is 85.1%). 3. The excessive lumbering, man-made destruction, violent typhoon, edible value of the seeds and genetic drift were the main reasons for the low-level genetic diversity of C. mannii and its endangered position. 4. The difference of the micro-environment and other random factors affecting the population should also be taken into full consideration in the study and in protection of such occasionally scattered plants. 5. Enforced measures should be taken to protect the present population, enlarge the population and lower the loss rate of its gene. Mt. Limulin should be chosen as a conservative spot because of its high genetic diversity and less destruction of the forest. Meanwhile, the protection of other populations should be enforced. 6. The differences within and between the populations are great based on different primers used. The change of proportions in polymorphic loci between the populations is more than that between the primers.展开更多
Plant germplasm resources is the material foundation and key point for agricultural production, crop breeding and bioengineering. China is one of the centers for the origin of the cultivated plants worldwide, as well ...Plant germplasm resources is the material foundation and key point for agricultural production, crop breeding and bioengineering. China is one of the centers for the origin of the cultivated plants worldwide, as well as one of the countries with most abundant plant resources and the highest biodiversity. Strengthening research in the conservation and utilization of plant germplasm resources is of significant value and importance. In this study, the present status of conservation, utilization, and existing problems of plant germplasm resources in China and around the world were reviewed; further, through analyzing measures taken by global countries for plant germplasm resources protection, countermeasures for plant germplasm resources conservation in China were also presented from three aspects, namely, collection and conservation, information network construction and national legislation and policies.展开更多
An approach was established using RP-HPLC (reversed-phase high-performance liquid chromatography) to identify ten species of Rhodiola, R. coccinea A. Bor, R. junggarica C.Y. Yang et N.R. Cui spn., R. heterodonta A. Bo...An approach was established using RP-HPLC (reversed-phase high-performance liquid chromatography) to identify ten species of Rhodiola, R. coccinea A. Bor, R. junggarica C.Y. Yang et N.R. Cui spn., R. heterodonta A. Bor, R. linearifolia A. Bor, R. pamiro alaiucm A. Bor, R. kaschgarica A. Bor, R. litwinowii A. Bor, R. gelida schrenk, R. rosea L. and R. quadrifide Fisch et Mey collected from the Tianshan Mountains areas of China. Chromatograms of alcohol-soluble proteins, generated from these ten Rhodiola spp. were compared. Each chromatogram of alcohol-soluble proteins came from a single seed of one wild species only. The results showed that when using a Waters Delta Pak. C18, 5 μm particle size reversed phase column (150 mm×3.9 mm), a linear gradient of 22%?55% solvent B with a flow rate of 1 ml/min and a run time of 67 min, the chromatography gave optimum separation of Rhodiola alcohol-soluble proteins. Chromatogram of each species was different and could be used to identify those species. Cluster analysis of genetic similarity coefficients of 37% to 60% showed a medium degree of genetic diversity among the species in these eco-areas. Cluster analysis showed that the ten species of Rhodiola can be divided into four clusters and yielded the general and unique biochemical markers of these species. RP-HPLC was shown to be a rapid, repeatable and reliable method for Rhodiola species identification and analysis of genetic diversity.展开更多
In recent years, with the rapid development of molecular biology, molecular markers have been widely used in genetic breeding of various crops including cowpea. However, molecular researches in cowpea are lack of syst...In recent years, with the rapid development of molecular biology, molecular markers have been widely used in genetic breeding of various crops including cowpea. However, molecular researches in cowpea are lack of systematic summary. This review presents an overview of accomplishments on different aspects of molecular markers in cowpea genetic breeding, such as genetic diversity analysis, genetic linkage map construction, QTL mapping, etc. Furthermore, it provides the discussion of some existing problems about molecular markers applied in cowpea breeding and the prospect of the future development. The authors find that SSR is the most frequently used molecular marker, while SNP has not been used in the genetic diversity analysis of cowpea. And the authors also conclude that more QTL of cowpea should be located and more molecular markers linked to resistance gene should be found. This will be useful for scientists and breeders to research cowpea with the aid of molecular markers, thus accelerating improvement of cowpea varieties.展开更多
The Chinese tree shrew (Tupaia belangeri chinensis) is a small experimental animal with a close affinity to primates. This species has long been proposed to be an alternative experimental animal to primates in biomedi...The Chinese tree shrew (Tupaia belangeri chinensis) is a small experimental animal with a close affinity to primates. This species has long been proposed to be an alternative experimental animal to primates in biomedical research. Despite decades of study, there is no pure breed for this animal, and the overall genetic diversity of wild tree shrews remains largely unknown. In order to obtain a set of genetic markers for evaluating the genetic diversity of tree shrew wild populations and tracing the lineages in inbreeding populations, we developed 12 polymorphic microsatellite markers from the genomic DNA of the tree shrew. An analysis of a wild population of 117 individuals collected from the suburb of Kunming, China, showed that these loci exhibited a highly expected heterozygosity (0.616). These 12 microsatellites were sufficient for individual identification and parentage analysis. The microsatellite markers developed in this study will be of use in evaluating genetic diversity and lineage tracing for the tree shrew.展开更多
Alfalfa (Medicago sativa L.) is being grown in harsh environment in Iraq and is mostly subjected to abiotic stresses such as drought, salinity, pH and temperature. Both alfalfa and its nitrogen fixing symbiotic bact...Alfalfa (Medicago sativa L.) is being grown in harsh environment in Iraq and is mostly subjected to abiotic stresses such as drought, salinity, pH and temperature. Both alfalfa and its nitrogen fixing symbiotic bacteria Sinorhizobium meliloti are affected by these environmental stresses. Enhancing nitrogen fixation biologically could be achieved through selection of tolerant strains of S. meliloti to these environmental stresses and inoculating them to the crop, also growing tolerant cultivars. This study examines phenotypic diversity for tolerance to drought, salinity, temperature and pH. Sixty isolates sampled from different areas of Iraq. The results revealed high degree of phenotypic diversity in Sinorhizobium populations. Furthermore, the isolates which showed tolerance to drought stress also showed tolerance to salinity and high degree of temperature, indicating direct relationship between three physiological path ways. Also 58.3% of drought tolerant isolates were alkaline tolerant they tolerated up to pH 9, point to say almost all drought tolerant isolates in this study illustrated strong + positive reaction to catalase enzyme. And 91.6% themes were negative for Gelatinase enzyme test. While only 50% of drought sensitive isolates were negative for drought sensitive isolates could grow at high temperature (42 ℃).展开更多
The oceans account for 71% of the Earth’s surface and are rich in the most advantageous and characteristic resources of marine microbes. The research on diversity is the key point for exploring and exploiting marine ...The oceans account for 71% of the Earth’s surface and are rich in the most advantageous and characteristic resources of marine microbes. The research on diversity is the key point for exploring and exploiting marine microbial resources. Giving attention to species diversity and genetic diversity of marine microbes, discovering novel metabolites with multiple functions, revealing key secondary metabolic process and the main regulation mechanisms in marine microbes, and developing a new technology of biosynthesis, are the important foundation for discovering innovative drugs and developing functional products with characteristics. The present paper has reviewed the recent advances in the four research areas of marine microbial species diversity, genetic diversity, chemical diversity and metabolic diversity in China.展开更多
Biological diversity involves genetic, species, and ecosystem diversity. Genetic diversity denotes the variation within species in the functional units of heredity present in any plant or animal, microbial or other or...Biological diversity involves genetic, species, and ecosystem diversity. Genetic diversity denotes the variation within species in the functional units of heredity present in any plant or animal, microbial or other origin of living things. Species diversity encompasses the variety of species--whether wild or domesticated, within a geographical area. This study assesses the economic value of crop productivity biodiversity in Ijebu Ode agricultural zone of Ogun State. The authors proposed a dynamic model of market equilibrium with vertical product differentiation that enabled us to take into account the economic consequences of respondents' monthly income and species crop of three different communities. The objectives of the study are to identify the personal and socio-economic characteristics of farmers and determine the importance of biodiversity in the study area using Simpson's Index. The result showed that 52.50% were male, majority (32.50%) were within the age range of 31 and 40 years old, 44.17% were married, 62.50% had household size of 6-10, and majority (45.83%) had secondary education while 46.67% had up to 20 years farming experience. In conclusion, the authors find that effective factors play an important role in explaining the support for biodiversity conservation, particularly when people do not have specific knowledge about species; while ecological-scientific considerations appear when people are well-informed.展开更多
Taro (Colocasia esculenta L. Schott) is an important underutilised crop in South Africa, East Africa and Indonesia. Three taro landraces, namely, Dumbe Lomfula (wild), KwaNgwanase and Umbumbulu, were collected fro...Taro (Colocasia esculenta L. Schott) is an important underutilised crop in South Africa, East Africa and Indonesia. Three taro landraces, namely, Dumbe Lomfula (wild), KwaNgwanase and Umbumbulu, were collected from two locations in KwaZulu-Natal (KZN), South Africa, and planted at two locations, Pietermaritzburg (KZN) and Roodeplaat, Pretoria. Ago-morphological characterisation of vegetative and corm characteristics were done four months after planting and at harvest, respectively. Sampling for DNA fingerprinting using five SSR primers was done using leaf material four months after planting. Agro-morphological characterisation was useful in showing differences between the wild landrace and the two cultivated landraces, as well as identification of dasheen and eddoe types. SSR primer characterisation showed that despite significant morphological difference, the wild Dumbe Lomfula and Umbumbulu landraces were closely related but different from the KwaNgwanase landrace. Although landraces showed great morphological variation, this did not necessarily imply genetic variation. It is concluded that SSR primers are more useful for characterising taro landraces.展开更多
RAPD (random amplified polymorphic DNA) markers were performed to fingerprint 20 varieties of maize. Twenty operon primers generated informative RAPD patterns and selected for further RAPD analysis. These 20 primers...RAPD (random amplified polymorphic DNA) markers were performed to fingerprint 20 varieties of maize. Twenty operon primers generated informative RAPD patterns and selected for further RAPD analysis. These 20 primers yielded 291 of main bands, out of which 169 were polymorphic bands across tested varieties. Each selected primer produced between 59 bands (OPC-01) to 142 bands (OPX-04). Amplification products (DNA amplicons) and fragments size ranged from 260 bp (OPT-06) to 2,365 bp (OPP-05). The largest number of polymorphic bands (20 bands) was produced by primer OPX-04 while, the lowest number of polymorphic bands (1 band) was produced by primer OPA-03. The primers of the most interest of this purpose were those that produced more variety specific DNA profiles, such as OPD-03, OPE-18, OPF-05, OPL-11 and OPX-04. The primer efficiency ranged from 0.20 in primer OPA-12 to 0.01 in primer OPA-03. The highest polymorphism and value of discrimination in this study were obtained with primers OPX-04, while, the lowest polymorphism and value of discrimination were obtained with primers OPA-03. The lowest genetic distance was 0.1941 between varieties Manlcet and Biotech Bag, while, the highest genetic distance was 0.6433 between varieties Pio 3751 and Buhooth 106. Cluster analysis (phylogenetic tree) by UPGMA (unweighted pair-group method of arithmetic means) based dendrogram revealed that they were four main genetic groups. The overall analysis of the results reveals that the genetic relationships among the maize varieties were related to some of their morphological characters as well as to their geographical origins at the molecular genetics.展开更多
The genetic diversity of 79 accessions regenerated from "miniature seeds" of loquat (Eriobotrya japonica Lindl. cv. 'Dawuxing') was analyzed based on 13 morphological characteristics of leaves in this study, in ...The genetic diversity of 79 accessions regenerated from "miniature seeds" of loquat (Eriobotrya japonica Lindl. cv. 'Dawuxing') was analyzed based on 13 morphological characteristics of leaves in this study, in order to provide important morphological basis for breeding new varieties and materials through "miniature seed" breeding method in loquat. The results showed that there was abundant genetic diversity in leaf morphological characteristics of regenerated plants (D=0.785), especially indicated by diversity indexes of leaf length (D=0.991), leaf width (D=0.994), petiole length (D=0.982), petiole thickness (D=0.995) and leaf thickness (D=0.987). And all the characteristic values varied broadly with coefficients of variation ranging from 9.84% to 40.09%; 79 accessions were divided into 6 groups by UPGMA method, there were significant differences in leaf morphological traits among the 6 groups; Group I and group VI were quite different from other groups and parent plants (cv. "Dawuxing"). The leaves of group I were darkgreen, large, hard and thick with long and thick petioles; while those of group VI were yellowgreen, small, thin and soft with slender petioles. These two groups were important excellent germplasm. Based on the abundant genetic diversity in leaf morphological characteristics, the breeding via "miniature seeds" was considered as an efficient method for broadening the germplasm resources and breeding new varieties of loquat.展开更多
Hybridisation was traditionally considered rare on coral reefs. However, a rapid increase in hybrid studies over the last 20 years has revealed that hybridisation on coral reefs is common and widespread. In this revie...Hybridisation was traditionally considered rare on coral reefs. However, a rapid increase in hybrid studies over the last 20 years has revealed that hybridisation on coral reefs is common and widespread. In this review, we summarise the growing body of evidence arising from studies on stony corals and reef fishes to verify the occurrence of hybridisatiori, and we examine the influence hybridisation has had on the enormous level of biodiversity present on coral reefs. We discuss the challenges of dis- tinguishing hybridisation from alternative hypotheses (e.g. incomplete lineage sorting). This review also explores the evolutio- nary consequences of hybridisation, which range from increasing genetic diversity and the production of novel lineages that may outperform the parent species, to reverse speciation and extinction by genetic swamping. Instances of hybridisation can be natural or occur as a result of human impacts (e.g. habitat degradation) and distinguishing between these two very different causal me- chanisms is important for management. Currently, the legislative status of hybrids is unclear and hybrids are rarely protected in conservation programs. Failing to adequately manage hybridisation and hybrid lineages may lead to potential losses of evolutio- nary novelty, declines in phylogenetic diversity or species extinctions. To conserve existing coral reef biodiversity, and the processes that generate biodiversity, conservation policies must be re-defined and instances of hybridisation must be assessed and managed on a case-by-case basis [Current Zoology 61 (1): 132 145, 2015].展开更多
Reinforcement--the process whereby maladaptive hybridization leads to the strengthening of prezygotic isolation between species--has a long history in the study of speciation. Because reinforcement affects traits invo...Reinforcement--the process whereby maladaptive hybridization leads to the strengthening of prezygotic isolation between species--has a long history in the study of speciation. Because reinforcement affects traits involved in mate choice and fertility, it can have indirect effects on reproductive isolation between populations within species. Here we review examples of these "cascading effects of reinforcement" (CER) and discuss different mechanisms through which they can arise. We discuss three factors that are predicted to influence the potential occurrence of CER: rates of gene flow among populations, the strength of selection acting on the traits involved in reinforcement, and the genetic basis of those traits. We suggest that CER is likely if (1) the rate of gene flow between conspecific populations is low; (2) divergent selection acts on phenotypes involved in reinforcement between sympatric and allopatric populations; and (3) the genetic response to reinforcement differs among conspecific populations subject to parallel reinforcing selection. Future work continuing to address gene flow, selection, and the genetic basis of the traits involved in the reinforcement will help develop a better understanding of reinforcement as a process driving the production of species diversity, both directly and incidentally.展开更多
Aims Species-rich plant communities are more resistant to invasions.In the past decade it was demonstrated that genetic variation also has many ecological effects.In our study we aimed to test whether the patterns of ...Aims Species-rich plant communities are more resistant to invasions.In the past decade it was demonstrated that genetic variation also has many ecological effects.In our study we aimed to test whether the patterns of response to the genetic diversity of a resident species differ between colonizing species of different growth forms and whether the response is affected by soil nutrients.Methods We established experimental stands of a common grass,Festuca rubra,harbouring three levels of genetic diversity(1,6 or 18 clonal genotypes,referred to as genotypic diversity)under two soil nutrient levels.In the fourth year after the stands were established,we sowed a mixture of four colonizers into the stands:a stoloniferous legume(Trifolium repens),a broad-leaf tussock grass(Anthoxanthum odoratum),a largerosette forb(Plantago lanceolata)and a small-rosette forb(Campanula rotundifolia).We observed species establishment and growth over 3 years.We tested whether colonization success depended on genotypic diversity,specific Festuca genotypes,soil nutrients and colonizer growth form.Important Findings The colonization success and biomass of the colonizers were significantly affected by the genotypic diversity and the genotype identity of the resident clonal grass.The response,however,differed between the colonizers.The strongest response to the genotypic diversity of the resident species was observed in the tussock grass with a growth form and architecture similar to the resident species.The large-rosette species responded in early stages of growth whereas the stoloniferous legume did not respond at all.The intraspecific genotypic diversity and genotype identity of the resident species play an important role in the assembly of plant communities.展开更多
The Fleming-Viot process with parent-independent mutation process is one particular neutral pop- ulation genetic model. As time goes by, some initial species are replaced by mutated ones gradually. Once the population...The Fleming-Viot process with parent-independent mutation process is one particular neutral pop- ulation genetic model. As time goes by, some initial species are replaced by mutated ones gradually. Once the population mutation rate is high, mutated species will elbow out all the initial species very quickly. Small-time behavior in thls case seems to be the key to understand this fast transition. The small-time asymptotic results related to time scale t and a(O)t, where lim0→∞θ θa(θ) = O, are obtained by Dawson and Shni (1998, 2001), Shui and Xiong (2002), and Xiang and Zhang (2005), respectively. Only the behavior under the scale t(θ), where limθ→∞θt(θ) = 0 and limθ→∞(O) =∞ was left untouched. In this paper, the weak limits under various small-time scales are obtained. Of particular interest is the large deviations for the small-time transient sam- pling distributions, which reveal interesting phase transition. Interestingly, such a phase transition is uniquely determined by some species diversity indices.展开更多
文摘Using RAPD technique, the DNA diversity of Cephalotaxus mannii Hook. f., its genetic diversity pattern, the reasons for its endangered position and conservative approaches were studied. The results show that: 1. The genetic diversity of C. mannii collected from five localities in Hainan is low, and its adaptability to environmental change is weak. 2. The differences of genetic diversity between intra- and inter-populations are great, and the major variation distributes within the population (DNA diversity is 85.1%). 3. The excessive lumbering, man-made destruction, violent typhoon, edible value of the seeds and genetic drift were the main reasons for the low-level genetic diversity of C. mannii and its endangered position. 4. The difference of the micro-environment and other random factors affecting the population should also be taken into full consideration in the study and in protection of such occasionally scattered plants. 5. Enforced measures should be taken to protect the present population, enlarge the population and lower the loss rate of its gene. Mt. Limulin should be chosen as a conservative spot because of its high genetic diversity and less destruction of the forest. Meanwhile, the protection of other populations should be enforced. 6. The differences within and between the populations are great based on different primers used. The change of proportions in polymorphic loci between the populations is more than that between the primers.
基金Supported by the Beijing Nova Program(2008B37)the Major Research Program of Beijing Municipal Commission of Science and Technology(D131100000413001)+2 种基金National Key Technologies R&D Program(2012BAK26B03)the Special Fund for Construction of Scientific and Technological Innovation Ability of Beijing Academy of Agriculture and Forestry Sciencesthe Special Research Fund for the Youth of Beijing Academy of Agriculture and Forestry Sciences(QNJJ201211)~~
文摘Plant germplasm resources is the material foundation and key point for agricultural production, crop breeding and bioengineering. China is one of the centers for the origin of the cultivated plants worldwide, as well as one of the countries with most abundant plant resources and the highest biodiversity. Strengthening research in the conservation and utilization of plant germplasm resources is of significant value and importance. In this study, the present status of conservation, utilization, and existing problems of plant germplasm resources in China and around the world were reviewed; further, through analyzing measures taken by global countries for plant germplasm resources protection, countermeasures for plant germplasm resources conservation in China were also presented from three aspects, namely, collection and conservation, information network construction and national legislation and policies.
基金Project (No. 30470330) supported by the National Natural ScienceFoundation of China
文摘An approach was established using RP-HPLC (reversed-phase high-performance liquid chromatography) to identify ten species of Rhodiola, R. coccinea A. Bor, R. junggarica C.Y. Yang et N.R. Cui spn., R. heterodonta A. Bor, R. linearifolia A. Bor, R. pamiro alaiucm A. Bor, R. kaschgarica A. Bor, R. litwinowii A. Bor, R. gelida schrenk, R. rosea L. and R. quadrifide Fisch et Mey collected from the Tianshan Mountains areas of China. Chromatograms of alcohol-soluble proteins, generated from these ten Rhodiola spp. were compared. Each chromatogram of alcohol-soluble proteins came from a single seed of one wild species only. The results showed that when using a Waters Delta Pak. C18, 5 μm particle size reversed phase column (150 mm×3.9 mm), a linear gradient of 22%?55% solvent B with a flow rate of 1 ml/min and a run time of 67 min, the chromatography gave optimum separation of Rhodiola alcohol-soluble proteins. Chromatogram of each species was different and could be used to identify those species. Cluster analysis of genetic similarity coefficients of 37% to 60% showed a medium degree of genetic diversity among the species in these eco-areas. Cluster analysis showed that the ten species of Rhodiola can be divided into four clusters and yielded the general and unique biochemical markers of these species. RP-HPLC was shown to be a rapid, repeatable and reliable method for Rhodiola species identification and analysis of genetic diversity.
文摘In recent years, with the rapid development of molecular biology, molecular markers have been widely used in genetic breeding of various crops including cowpea. However, molecular researches in cowpea are lack of systematic summary. This review presents an overview of accomplishments on different aspects of molecular markers in cowpea genetic breeding, such as genetic diversity analysis, genetic linkage map construction, QTL mapping, etc. Furthermore, it provides the discussion of some existing problems about molecular markers applied in cowpea breeding and the prospect of the future development. The authors find that SSR is the most frequently used molecular marker, while SNP has not been used in the genetic diversity analysis of cowpea. And the authors also conclude that more QTL of cowpea should be located and more molecular markers linked to resistance gene should be found. This will be useful for scientists and breeders to research cowpea with the aid of molecular markers, thus accelerating improvement of cowpea varieties.
基金supported by the National 863 Project of China (2012AA021801)grants from Chinese Academy of Sciences (KSCX2-EW-R-11 and KSCX2-EW-J-23)Yunnan Province (2009CI119)
文摘The Chinese tree shrew (Tupaia belangeri chinensis) is a small experimental animal with a close affinity to primates. This species has long been proposed to be an alternative experimental animal to primates in biomedical research. Despite decades of study, there is no pure breed for this animal, and the overall genetic diversity of wild tree shrews remains largely unknown. In order to obtain a set of genetic markers for evaluating the genetic diversity of tree shrew wild populations and tracing the lineages in inbreeding populations, we developed 12 polymorphic microsatellite markers from the genomic DNA of the tree shrew. An analysis of a wild population of 117 individuals collected from the suburb of Kunming, China, showed that these loci exhibited a highly expected heterozygosity (0.616). These 12 microsatellites were sufficient for individual identification and parentage analysis. The microsatellite markers developed in this study will be of use in evaluating genetic diversity and lineage tracing for the tree shrew.
文摘Alfalfa (Medicago sativa L.) is being grown in harsh environment in Iraq and is mostly subjected to abiotic stresses such as drought, salinity, pH and temperature. Both alfalfa and its nitrogen fixing symbiotic bacteria Sinorhizobium meliloti are affected by these environmental stresses. Enhancing nitrogen fixation biologically could be achieved through selection of tolerant strains of S. meliloti to these environmental stresses and inoculating them to the crop, also growing tolerant cultivars. This study examines phenotypic diversity for tolerance to drought, salinity, temperature and pH. Sixty isolates sampled from different areas of Iraq. The results revealed high degree of phenotypic diversity in Sinorhizobium populations. Furthermore, the isolates which showed tolerance to drought stress also showed tolerance to salinity and high degree of temperature, indicating direct relationship between three physiological path ways. Also 58.3% of drought tolerant isolates were alkaline tolerant they tolerated up to pH 9, point to say almost all drought tolerant isolates in this study illustrated strong + positive reaction to catalase enzyme. And 91.6% themes were negative for Gelatinase enzyme test. While only 50% of drought sensitive isolates were negative for drought sensitive isolates could grow at high temperature (42 ℃).
文摘The oceans account for 71% of the Earth’s surface and are rich in the most advantageous and characteristic resources of marine microbes. The research on diversity is the key point for exploring and exploiting marine microbial resources. Giving attention to species diversity and genetic diversity of marine microbes, discovering novel metabolites with multiple functions, revealing key secondary metabolic process and the main regulation mechanisms in marine microbes, and developing a new technology of biosynthesis, are the important foundation for discovering innovative drugs and developing functional products with characteristics. The present paper has reviewed the recent advances in the four research areas of marine microbial species diversity, genetic diversity, chemical diversity and metabolic diversity in China.
文摘Biological diversity involves genetic, species, and ecosystem diversity. Genetic diversity denotes the variation within species in the functional units of heredity present in any plant or animal, microbial or other origin of living things. Species diversity encompasses the variety of species--whether wild or domesticated, within a geographical area. This study assesses the economic value of crop productivity biodiversity in Ijebu Ode agricultural zone of Ogun State. The authors proposed a dynamic model of market equilibrium with vertical product differentiation that enabled us to take into account the economic consequences of respondents' monthly income and species crop of three different communities. The objectives of the study are to identify the personal and socio-economic characteristics of farmers and determine the importance of biodiversity in the study area using Simpson's Index. The result showed that 52.50% were male, majority (32.50%) were within the age range of 31 and 40 years old, 44.17% were married, 62.50% had household size of 6-10, and majority (45.83%) had secondary education while 46.67% had up to 20 years farming experience. In conclusion, the authors find that effective factors play an important role in explaining the support for biodiversity conservation, particularly when people do not have specific knowledge about species; while ecological-scientific considerations appear when people are well-informed.
文摘Taro (Colocasia esculenta L. Schott) is an important underutilised crop in South Africa, East Africa and Indonesia. Three taro landraces, namely, Dumbe Lomfula (wild), KwaNgwanase and Umbumbulu, were collected from two locations in KwaZulu-Natal (KZN), South Africa, and planted at two locations, Pietermaritzburg (KZN) and Roodeplaat, Pretoria. Ago-morphological characterisation of vegetative and corm characteristics were done four months after planting and at harvest, respectively. Sampling for DNA fingerprinting using five SSR primers was done using leaf material four months after planting. Agro-morphological characterisation was useful in showing differences between the wild landrace and the two cultivated landraces, as well as identification of dasheen and eddoe types. SSR primer characterisation showed that despite significant morphological difference, the wild Dumbe Lomfula and Umbumbulu landraces were closely related but different from the KwaNgwanase landrace. Although landraces showed great morphological variation, this did not necessarily imply genetic variation. It is concluded that SSR primers are more useful for characterising taro landraces.
文摘RAPD (random amplified polymorphic DNA) markers were performed to fingerprint 20 varieties of maize. Twenty operon primers generated informative RAPD patterns and selected for further RAPD analysis. These 20 primers yielded 291 of main bands, out of which 169 were polymorphic bands across tested varieties. Each selected primer produced between 59 bands (OPC-01) to 142 bands (OPX-04). Amplification products (DNA amplicons) and fragments size ranged from 260 bp (OPT-06) to 2,365 bp (OPP-05). The largest number of polymorphic bands (20 bands) was produced by primer OPX-04 while, the lowest number of polymorphic bands (1 band) was produced by primer OPA-03. The primers of the most interest of this purpose were those that produced more variety specific DNA profiles, such as OPD-03, OPE-18, OPF-05, OPL-11 and OPX-04. The primer efficiency ranged from 0.20 in primer OPA-12 to 0.01 in primer OPA-03. The highest polymorphism and value of discrimination in this study were obtained with primers OPX-04, while, the lowest polymorphism and value of discrimination were obtained with primers OPA-03. The lowest genetic distance was 0.1941 between varieties Manlcet and Biotech Bag, while, the highest genetic distance was 0.6433 between varieties Pio 3751 and Buhooth 106. Cluster analysis (phylogenetic tree) by UPGMA (unweighted pair-group method of arithmetic means) based dendrogram revealed that they were four main genetic groups. The overall analysis of the results reveals that the genetic relationships among the maize varieties were related to some of their morphological characters as well as to their geographical origins at the molecular genetics.
文摘The genetic diversity of 79 accessions regenerated from "miniature seeds" of loquat (Eriobotrya japonica Lindl. cv. 'Dawuxing') was analyzed based on 13 morphological characteristics of leaves in this study, in order to provide important morphological basis for breeding new varieties and materials through "miniature seed" breeding method in loquat. The results showed that there was abundant genetic diversity in leaf morphological characteristics of regenerated plants (D=0.785), especially indicated by diversity indexes of leaf length (D=0.991), leaf width (D=0.994), petiole length (D=0.982), petiole thickness (D=0.995) and leaf thickness (D=0.987). And all the characteristic values varied broadly with coefficients of variation ranging from 9.84% to 40.09%; 79 accessions were divided into 6 groups by UPGMA method, there were significant differences in leaf morphological traits among the 6 groups; Group I and group VI were quite different from other groups and parent plants (cv. "Dawuxing"). The leaves of group I were darkgreen, large, hard and thick with long and thick petioles; while those of group VI were yellowgreen, small, thin and soft with slender petioles. These two groups were important excellent germplasm. Based on the abundant genetic diversity in leaf morphological characteristics, the breeding via "miniature seeds" was considered as an efficient method for broadening the germplasm resources and breeding new varieties of loquat.
文摘Hybridisation was traditionally considered rare on coral reefs. However, a rapid increase in hybrid studies over the last 20 years has revealed that hybridisation on coral reefs is common and widespread. In this review, we summarise the growing body of evidence arising from studies on stony corals and reef fishes to verify the occurrence of hybridisatiori, and we examine the influence hybridisation has had on the enormous level of biodiversity present on coral reefs. We discuss the challenges of dis- tinguishing hybridisation from alternative hypotheses (e.g. incomplete lineage sorting). This review also explores the evolutio- nary consequences of hybridisation, which range from increasing genetic diversity and the production of novel lineages that may outperform the parent species, to reverse speciation and extinction by genetic swamping. Instances of hybridisation can be natural or occur as a result of human impacts (e.g. habitat degradation) and distinguishing between these two very different causal me- chanisms is important for management. Currently, the legislative status of hybrids is unclear and hybrids are rarely protected in conservation programs. Failing to adequately manage hybridisation and hybrid lineages may lead to potential losses of evolutio- nary novelty, declines in phylogenetic diversity or species extinctions. To conserve existing coral reef biodiversity, and the processes that generate biodiversity, conservation policies must be re-defined and instances of hybridisation must be assessed and managed on a case-by-case basis [Current Zoology 61 (1): 132 145, 2015].
文摘Reinforcement--the process whereby maladaptive hybridization leads to the strengthening of prezygotic isolation between species--has a long history in the study of speciation. Because reinforcement affects traits involved in mate choice and fertility, it can have indirect effects on reproductive isolation between populations within species. Here we review examples of these "cascading effects of reinforcement" (CER) and discuss different mechanisms through which they can arise. We discuss three factors that are predicted to influence the potential occurrence of CER: rates of gene flow among populations, the strength of selection acting on the traits involved in reinforcement, and the genetic basis of those traits. We suggest that CER is likely if (1) the rate of gene flow between conspecific populations is low; (2) divergent selection acts on phenotypes involved in reinforcement between sympatric and allopatric populations; and (3) the genetic response to reinforcement differs among conspecific populations subject to parallel reinforcing selection. Future work continuing to address gene flow, selection, and the genetic basis of the traits involved in the reinforcement will help develop a better understanding of reinforcement as a process driving the production of species diversity, both directly and incidentally.
基金supported by the Czech Science Foundation(grant number 19-00522S)partly by a long-term research development project of the Academy of Sciences of the Czech Republic grant number RVO 67985939 and the Ministry of Education,Youth and Sports.
文摘Aims Species-rich plant communities are more resistant to invasions.In the past decade it was demonstrated that genetic variation also has many ecological effects.In our study we aimed to test whether the patterns of response to the genetic diversity of a resident species differ between colonizing species of different growth forms and whether the response is affected by soil nutrients.Methods We established experimental stands of a common grass,Festuca rubra,harbouring three levels of genetic diversity(1,6 or 18 clonal genotypes,referred to as genotypic diversity)under two soil nutrient levels.In the fourth year after the stands were established,we sowed a mixture of four colonizers into the stands:a stoloniferous legume(Trifolium repens),a broad-leaf tussock grass(Anthoxanthum odoratum),a largerosette forb(Plantago lanceolata)and a small-rosette forb(Campanula rotundifolia).We observed species establishment and growth over 3 years.We tested whether colonization success depended on genotypic diversity,specific Festuca genotypes,soil nutrients and colonizer growth form.Important Findings The colonization success and biomass of the colonizers were significantly affected by the genotypic diversity and the genotype identity of the resident clonal grass.The response,however,differed between the colonizers.The strongest response to the genotypic diversity of the resident species was observed in the tussock grass with a growth form and architecture similar to the resident species.The large-rosette species responded in early stages of growth whereas the stoloniferous legume did not respond at all.The intraspecific genotypic diversity and genotype identity of the resident species play an important role in the assembly of plant communities.
基金supported by Fundamental Research Fund of Zhongnan University of Economics and Law (Grant No. 31541411208)
文摘The Fleming-Viot process with parent-independent mutation process is one particular neutral pop- ulation genetic model. As time goes by, some initial species are replaced by mutated ones gradually. Once the population mutation rate is high, mutated species will elbow out all the initial species very quickly. Small-time behavior in thls case seems to be the key to understand this fast transition. The small-time asymptotic results related to time scale t and a(O)t, where lim0→∞θ θa(θ) = O, are obtained by Dawson and Shni (1998, 2001), Shui and Xiong (2002), and Xiang and Zhang (2005), respectively. Only the behavior under the scale t(θ), where limθ→∞θt(θ) = 0 and limθ→∞(O) =∞ was left untouched. In this paper, the weak limits under various small-time scales are obtained. Of particular interest is the large deviations for the small-time transient sam- pling distributions, which reveal interesting phase transition. Interestingly, such a phase transition is uniquely determined by some species diversity indices.