scholarly journals Genetic Diversity and Genetic Structure of Different Types of Natural Populations inOsmanthus fragransLour. and the Relationships with Sex Ratio, Population Structure, and Geographic Isolation

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Shaoqing Hu ◽  
Shuai Wu ◽  
Yiguang Wang ◽  
Hongbo Zhao ◽  
Yuanyan Zhang
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Sex Ratio ◽  
Natural Populations ◽  
Sexual System ◽  
Geographic Isolation ◽  
Natural Distribution ◽  
Reproduction Mode ◽  
Osmanthus Fragrans ◽  
Different Types

Osmanthus fragransLour., an evergreen small tree, has the rare sexual system of androdioecy (coexistence of males and hermaphrodites), once with wide-spread natural distribution in the areas of the South Yangzi river basin. However, due to excessive human utilization, natural distribution became fragmented and the number and size of natural populations reduced sharply. With four different types of natural populations from the same region as research object, we aim to provide a comparative analysis on the relationships among genetic diversity, sexual system, population structure and size, and geographic isolation by ISSR. In genetic parameters ofNe,He, andI, the LQGC population had the highest value and the LQZGQ population had the lowest value. These indicated that LQGC population showed the highest genetic diversity, followed by QDH and JN population, and LQZGQ population exhibited the lowest genetic diversity. Genetic diversity in populations is closely related to population structure, reproduction mode, and sex ratio. However, there seems to be no obvious correlation between genetic diversity and population size. The results of AMOVA showed that genetic variations mostly occurred within populations. It indicates that no significant genetic differentiation among populations occurs, and geographic isolation has no significant effect on genetic diversity.

Regional divergence and inbreeding in Eucalyptus cladocalyx (Myrtaceae)

2003 ◽  
Vol 51 (4) ◽  
pp. 393 ◽  
Author(s):  
M. W. McDonald ◽  
M. Rawlings ◽  
P. A. Butcher ◽  
J. C. Bell
Keyword(s):  
Genetic Diversity ◽  
Natural Populations ◽  
South Australia ◽  
Natural Distribution ◽  
Flinders Ranges ◽  
Outcrossing Rates ◽  
Low Levels ◽  
Western Victoria ◽  
Ornamental Species ◽  
Regional Divergence

Eucalyptus cladocalyx F.Muell. is a widely cultivated tree in dryland southern Australia. It is grown for firewood, timber production and as a windbreak and ornamental species. Natural populations of E. cladocalyx are endemic to South Australia where they occur in three disjunct regions. This study assessed the mating system and patterns of genetic diversity in natural populations of E. cladocalyx by using allozymes. Populations had relatively low levels of genetic diversity (HE = 0.148) and high levels of genetic divergence (θ = 0.26) among populations, similar to other regionally distributed eucalypts. Populations clustered into three distinct groups, which corresponded to its disjunct natural distribution. Genetic differentiation among populations and between regions was highly significant. Relatively high levels of inbreeding (tm = 0.57) were detected in natural populations of E.�cladocalyx. Outcrossing rates were highly variable among families, ranging from 0 to 100%. One-third of families from four populations had outcrossing rates that were not significantly different from zero. The origins of three commercially significant, cultivated stands of E. cladocalyx were also assessed. Allozyme profiles of cultivated stands from Wail and Lismore in western Victoria suggested origins in the Wirrabara region of the southern Flinders Ranges, while a cultivated stand of E. cladocalyx var. nana Hort. ex Yates had an allozyme profile consistent with origins in the Eyre Peninsula region. The results are discussed in relation to the species' morphological variation, biogeography and the implications for its domestication and conservation.

Genetic diversity and population structure of Vigna exilis and Vigna grandiflora (Phaseoleae, Fabaceae) from Thailand based on microsatellite variation

Botany ◽  
2013 ◽  
Vol 91 (10) ◽  
pp. 653-661 ◽  
Author(s):  
Anochar Kaewwongwal ◽  
Arunee Jetsadu ◽  
Prakit Somta ◽  
Sompong Chankaew ◽  
Peerasak Srinives
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Allelic Richness ◽  
Gene Diversity ◽  
In Situ Conservation ◽  
Natural Populations ◽  
Microsatellite Variation ◽  
Genetic Clusters ◽  
Simple Sequence

The objective of this research was to determine the genetic diversity and population structure of natural populations of two rare wild species of Asian Vigna (Phaseoleae, Fabaceae), Vigna exilis Tateishi & Maxted and Vigna grandiflora (Prain) Tateishi & Maxted, from Thailand. Employing 21 simple sequence repeat markers, 107 and 85 individuals from seven and five natural populations of V. exilis and V. grandiflora, respectively, were analyzed. In total, the markers detected 196 alleles for V. exilis and 219 alleles for V. grandiflora. Vigna exilis populations showed lower average values in number of alleles, allelic richness, observed heterozygosity, gene diversity, and outcrossing rate than V. grandiflora populations, namely 58.00% versus 114.60%, 51.96% versus 74.80%, 0.02% versus 0.18%, 0.40% versus 0.66%, and 3.24% versus 17.41%, respectively. Pairwise FST among populations demonstrated that V. exilis was much more differentiated than V. grandiflora. Analysis of molecular variance revealed that 41.83% and 15.06% of total variation resided among the populations of V. exilis and V. grandiflora, respectively. Seven and two genetic clusters were detected for V. grandiflora and V. exilis by STRUCTURE analysis. Our findings suggest that different strategies are required for in situ conservation of the two species. All V. exilis populations, or as many as possible, should be conserved to protect genetic resources of this species, while a few V. grandiflora populations can capture the majority of its genetic variation.

Schistosome genetic diversity: the implications of population structure as detected with microsatellite markers

Parasitology ◽  
2002 ◽  
Vol 125 (7) ◽  
pp. S51-S59 ◽  
Author(s):  
J. CURTIS ◽  
R. E. SORENSEN ◽  
D. J. MINCHELLA
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Variation ◽  
Molecular Markers ◽  
Microsatellite Markers ◽  
Natural Populations ◽  
Mitochondrial Marker ◽  
Tropical Regions ◽  
Blood Flukes

Blood flukes in the genus Schistosoma are important human parasites in tropical regions. A substantial amount of genetic diversity has been described in populations of these parasites using molecular markers. We first consider the extent of genetic variation found in Schistosoma mansoni and some factors that may be contributing to this variation. Recently, though, attempts have been made to analyze not only the genetic diversity but how that diversity is partitioned within natural populations of schistosomes. Studies with non-allelic molecular markers (e.g. RAPDs and mtVNTRs) have indicated that schistosome populations exhibit varying levels of gene flow among component subpopulations. The recent characterization of microsatellite markers for S. mansoni provided an opportunity to study schistosome population structure within a population of schistosomes from a single Brazilian village using allelic markers. Whereas the detection of population structure depends strongly on the type of analysis with a mitochondrial marker, analyses with a set of seven microsatellite loci consistently revealed moderate genetic differentiation when village boroughs were used to define parasite subpopulations and greater subdivision when human hosts defined subpopulations. Finally, we discuss the implications that such strong population structure might have on schistosome epidemiology.

Low genetic diversity at allozyme loci in Juglans cinerea

2000 ◽  
Vol 78 (9) ◽  
pp. 1238-1243 ◽  
Author(s):  
Ricardo Morin ◽  
Jean Beaulieu ◽  
Marie Deslauriers ◽  
Gaëtan Daoust ◽  
Jean Bousquet
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Deciduous Forest ◽  
Polymorphic Locus ◽  
Natural Populations ◽  
Minor Component ◽  
Temperate Deciduous Forest ◽  
Juglans Cinerea ◽  
Low Genetic Diversity ◽  
Allozyme Loci

Butternut (Juglans cinerea L.) is a minor component of the temperate deciduous forest region of northeastern North America, but it is severely affected by the butternut canker (Sirococcus clavigignenti-juglandacearum Nair, Kostichka, and Kuntz) in the southern part of its natural range. Genetic diversity and population structure in as-yet unaffected or only slightly affected natural populations were evaluated at 12 isozyme loci. The genetic diversity estimates were low with values much below those estimated in other species of the same genus or in boreal tree species, with 25 and 13.9% polymorphic loci at the species and population levels, respectively; 1.3 and 2.3 alleles per locus and per polymorphic locus, respectively, at the species level; and an average observed heterozygosity of 0.028. Population differentiation was low, with the exception of one unique population. The implications for advanced conservation are discussed.Key words: butternut, isozymes, Sirococcus, canker, population structure.

scholarly journals Chloroplast microsatellites reveal genetic diversity and population structure in natural populations of Himalayan Cedar (Cedrus deodara (Roxb.) G. Don) in India

2020 ◽  
Vol 69 (1) ◽  
pp. 86-93
Author(s):  
H. S. Ginwal ◽  
Rajesh Sharma ◽  
Priti Chauhan ◽  
Kirti Chamling Rai ◽  
Santan Barthwal
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Natural Populations ◽  
Conservation Strategies ◽  
Restricted Gene Flow ◽  
Chloroplast Microsatellites ◽  
Timber Species ◽  
Western Himalayas ◽  
Cedrus Deodara ◽  
High Level

AbstractHimalayan cedar (Cedrus deodara) is one of the most important temperate timber species of Western Himalayas and is considered to be among the endangered conifer species in the region. Knowledge of genetic diversity and population structure will help guide gene conservation strategies for this species. Ten polymorphic chloroplast microsatellites (cpSSR) were used to study genetic diversity and population structure in twenty one natural populations of C. deodara throughout its entire distribution range in Western Himalayas. When alleles at each of the 10 loci were jointly analysed, 254 different haplotypes were identified among 1050 individuals. The cpSSRs indicate that C. deodara forests maintain a moderately high level of genetic diversity (mean h = 0.79 ). AMOVA analysis showed that most of the diversity in C. deodara occurs within populations. Bayesian analysis for population structure (BAPS) revealed spatial structuration of the variation (22 % of the total variation) and substructuring captured nineteen genetic clusters in the entire divisions of the populations. Most of the populations were clustered independently with minor admixtures. The distribution of genetic diversity and sub-structuring of C. deodara may be due to restricted gene flow due to geographic isolation, genetic drift, and natural selection. These findings indicated existence of genetically distinct and different high diversity and low diversity clusters, which are potential groups of populations that require attention for their conservation and management. The results are interpreted in context of future conservation plans for C. deodara.

scholarly journals Genetic Diversity and Population Structure Revealed by SSR Markers on Endemic Species Osmanthus serrulatus Rehder from Southwestern Sichuan Basin, China

Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1365
Author(s):  
Lin Chen ◽  
Tingting Pan ◽  
Huirong Qian ◽  
Min Zhang ◽  
Guodong Yang ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Ssr Markers ◽  
Sichuan Basin ◽  
Polymorphic Information Content ◽  
Population Decline ◽  
Natural Populations ◽  
Genetic Population ◽  
Endangered Status ◽  
High Level

Osmanthus serrulatus Rehder (Oleaceae) is an endemic spring-flowering species in China. It is narrowly distributed in the southwestern Sichuan Basin, and is facing the unprecedented threat of extinction due to problems associated with natural regeneration, habitat fragmentation and persistent and serious human interference. Here, the genetic diversity and population structure of 262 individuals from ten natural populations were analyzed using 18 microsatellites (SSR) markers. In total, 465 alleles were detected across 262 individuals, with a high polymorphic information content (PIC = 0.893). A high level of genetic diversity was inferred from the genetic diversity parameters (He = 0.694, I = 1.492 and PPL = 98.33%). AMOVA showed that a 21.55% genetic variation existed among populations and the mean pairwise Fst (0.215) indicated moderate genetic population differentiation. The ten populations were basically divided into three groups, including two obviously independent groups. Our results indicate that multiple factors were responsible for the complicated genetic relationship and endangered status of O. serrulatus. The concentrated distribution seems to be the key factor causing endangerment, and poor regeneration, human-induced habitat loss and fragmentation seem to be the primary factors in the population decline and further genetic diversity loss. These findings will assist in future conservation management and the scientific breeding of O. serrulatus.

scholarly journals Population Genetic Diversity and Structure of an Endangered Salicaceae Species in Northeast China: Chosenia arbutifolia (Pall.) A. Skv.

Forests ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1282
Author(s):  
Yu Wang ◽  
Zhongyi Jiao ◽  
Jiwei Zheng ◽  
Jie Zhou ◽  
Baosong Wang ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Management Strategies ◽  
Natural Populations ◽  
Snp Markers ◽  
Fixation Index ◽  
Landscape Genomics ◽  
Population Structure Analysis ◽  
Genetic Diversity And Structure ◽  
Chosenia Arbutifolia

Chosenia arbutifolia (Pall.) A. Skv. is a unique and endangered species belonging to the Salicaceae family. It has great potential for ornamental and industrial use. However, human interference has led to a decrease in and fragmentation of its natural populations in the past two decades. To effectively evaluate, utilize, and conserve available resources, the genetic diversity and population structure of C. arbutifolia were analyzed in this study. A total of 142 individuals from ten provenances were sampled and sequenced. Moderate diversity was detected among these, with a mean expected heterozygosity and Shannon’s Wiener index of 0.3505 and 0.5258, respectively. The inbreeding coefficient was negative, indicating a significant excess of heterozygotes. The fixation index varied from 0.0068 to 0.3063, showing a varied genetic differentiation between populations. Analysis of molecular variance demonstrated that differentiation accounted for 82.23% of the total variation among individuals, while the remaining 17.77% variation was between populations. Furthermore, the results of population structure analysis indicated that the 142 individuals originated from three primitive groups. To provide genetic information and help design conservation and management strategies, landscape genomics analysis was performed by investigating loci associated with environmental variables. Eighteen SNP markers were associated with altitude and annual average temperature, of which five were ascribed with specific functions. In conclusion, the current study furthers the understanding of C. arbutifolia genetic architecture and provides insights for germplasm protection.

scholarly journals Conservation aspects of natural populations and captive-bred stocks of turbot (Scophthalmus maximus) and Dover sole (Solea solea) using estimates of genetic diversity

2007 ◽  
Vol 64 (6) ◽  
pp. 1173-1181 ◽  
Author(s):  
Athanasios Exadactylos ◽  
Mark J. Rigby ◽  
Audrey J. Geffen ◽  
John P. Thorpe
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Natural Populations ◽  
Genetic Data ◽  
Scophthalmus Maximus ◽  
Effective Population ◽  
Solea Solea ◽  
Population Sizes ◽  
Turbot Scophthalmus Maximus ◽  
Dover Sole

Exadactylos, A., Rigby, M. J., Geffen, A. J., and Thorpe, J. P. 2007. Conservation aspects of natural populations and captive-bred stocks of turbot (Scophthalmus maximus) and Dover sole (Solea solea) using estimates of genetic diversity. – ICES Journal of marine Science, 64: 1173–1181. Population genetic analyses have been highly successful in predicting inter- and intraspecific evolutionary relationships, levels of gene flow, genetic divergence, and effective population sizes. Parameters estimated are evolutionary averages and are therefore relevant for addressing contemporary ecological or conservation issues. Changes in genetic variation within the range of a species may indicate patterns of population structure resulting from past ecological and demographic events that are otherwise difficult to infer, so may provide an insight into evolutionary development. Genetic data, drawn from 14 enzyme loci amplified from two populations of turbot (Scophthalmus maximus) and five populations of Dover sole (Solea solea) from the Irish Sea were used to examine population structure estimated from measures of genetic diversity. The aim was to provide an empirical assessment of whether artificial propagation poses a genetic threat to conservation of naturally spawning populations, and whether the fitness for natural spawning and rearing can be rapidly and substantially reduced or increased by artificial propagation. Because of prolonged overfishing, turbot and sole populations in the region are below natural levels, and survive in small local populations in fragmented habitats. Genetic data derived from allozymes have shown that populations are characterized by relatively low levels of genetic diversity. A hypothetical model supporting genetic population substructure, such as range expansion with founder-flush effects, and subsequent population decline with small effective population sizes was considered. Observations support our belief that conservation measures based on genetic diversity have to be developed to ensure the survival of this diverse gene pool.

scholarly journals Genetic Diversity and Population Structure of Chinese Corylus heterophylla and Corylus kweichowensis Using Simple Sequence Repeat Markers

2020 ◽  
Vol 145 (5) ◽  
pp. 289-298
Author(s):  
Tiantian Zhao ◽  
Wenxu Ma ◽  
Qinghua Ma ◽  
Zhen Yang ◽  
Lisong Liang ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Relationships ◽  
In Situ Conservation ◽  
Geographic Distance ◽  
Natural Populations ◽  
Distinct Species ◽  
Mantel Test ◽  
Conservation Of Genetic Resources ◽  
Genetic Clusters

Corylus heterophylla and Corylus kweichowensis are economically and ecologically important nut-producing woody shrubs that are distributed across northern and southern regions of China. However, few studies have examined the genetic diversity and genetic relationships between C. heterophylla and C. kweichowensis, and their taxonomic relationships have been questioned. In this study, 796 individuals collected from 34 natural populations (21 C. heterophylla and 13 C. kweichowensis populations) were investigated to assess the genetic diversity and population structure using 11 microsatellite loci. Analysis of molecular variance revealed that genetic differentiation of C. heterophylla and C. kweichowensis within populations accounted for 93.57% and 88.91% of total variation, respectively. The C. heterophylla and C. kweichowensis populations as a whole group were analyzed by multiple programs, which showed that the 34 populations were divided into two genetic clusters. One cluster included 21 C. heterophylla populations, and the second cluster contained 13 C. kweichowensis populations. We conclude from these results that C. heterophylla and C. kweichowensis are distinct species. The Mantel test showed that the genetic distance was significantly correlated with the geographic distance (r = 0.580, P < 0.001). The populations of C. heterophylla [e.g., populations WC (Weichang), MS (Mishan), and WA (Wu’an)] and C. kweichowensis [e.g., populations YX (Yuexi), ZP (Zhenping), LA (Lin’an), and TB (Taibai)] with high allelic richness are considered suitable for in situ conservation. Our study provides valuable information for breeding and conservation of genetic resources of C. heterophylla, C. kweichowensis, and related species.

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