scholarly journals Small-scale spatial genetic structure of Asarum sieboldii metapopulation in a valley

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Hyeon Jin Jeong ◽  
Jae Geun Kim
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Spatial Genetic Structure ◽  
Dispersal Distance ◽  
Forest Understory ◽  
Small Scale ◽  
Low Density ◽  
Stochastic Events

Abstract Background Asarum sieboldii Miq., a species of forest understory vegetation, is an herbaceous perennial belonging to the family Aristolochiaceae. The metapopulation of A. sieboldii is distributed sparsely and has a short seed dispersal distance by ants as their seed distributor. It is known that many flowers of A. sieboldii depend on self-fertilization. Because these characteristics can affect negatively in genetic structure, investigating habitat structure and assessment of genetic structure is needed. A total of 27 individuals in a valley were sampled for measuring genetic diversity, genetic distance, and genetic differentiation by RAPD-PCR. Results The habitat areas of A. sieboldii metapopulation were relatively small (3.78~33.60 m2) and population density was very low (five to seven individuals in 20×20 m quadrat). The habitat of A. sieboldii was a very shady (relative light intensity = 0.9%) and mature forest with a high evenness value (J = 0.81~0.99) and a low dominance value (D = 0.19~0.28). The total genetic diversity of A. sieboldii was quite high (h = 0.338, I = 0.506). A total of 33 band loci were observed in five selected primers, and 31 band loci (94%) were polymorphic. However, genetic differentiation along the valley was highly progressed (Gst = 0.548, Nm = 0.412). The average genetic distance between subpopulations was 0.387. The results of AMOVA showed 52.77% of variance occurs among populations, which is evidence of population structuring. Conclusions It is expected that a small-scale founder effect had occurred, an individual spread far from the original subpopulation formed a new subpopulation. However, geographical distance between individuals would have been far and genetic flow occurred only within each subpopulation because of the low density of population. This made significant genetic distance between the original and new population by distance. Although genetic diversity of A. sieboldii metapopulation is not as low as concerned, the subpopulation of A. sieboldii can disappear by stochastic events due to small subpopulation size and low density of population. To prevent genetic isolation and to enhance the stable population size, conservative efforts such as increasing the size of each subpopulation or the connection between subpopulations are needed.

Genetic differentiation of regional populations of the widespread Asiatic toad (Bufo gargarizans), as revealed by development of novel microsatellite markers

2018 ◽  
Vol 66 (6) ◽  
pp. 335
Author(s):  
T. Pan ◽  
P. Yan ◽  
M. Yang ◽  
H. Wang ◽  
I. Ali ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Yangtze River ◽  
The Yangtze River ◽  
Geographic Scale ◽  
Widespread Species ◽  
Bufo Gargarizans ◽  
Toad Bufo

Dispersal is a key component of a species’ life history, by influencing population persistence, genetic structure, adaptation and maintenance of genetic diversity. The Asiatic toad (Bufo gargarizans) is a widespread species in east Asia. However, we still have no knowledge of what kind of geographical scale equates to genetic differentiation within B. gargarizans. In this study, the population genetics of B. gargarizans was studied at five localities, with the Yangtze River running through the sampling area, in order to detect the level of genetic differentiation and the natural barriers to the species’ dispersal on a small geographic scale, by means of the development and use of novel microsatellite loci. These markers revealed a relatively high level of genetic diversity. Distinct genetic structure among populations in B. gargarizans was observed, as described by genetic distance, AMOVA, PCA and Geneland results. A weak but significant positive correlation between genetic distance and geographical distance. The combination of these findings suggests that the Yangtze River and geographic distance may act as effective barriers for B. gargarizans. These results serve as benchmark data for understanding the impacts of dispersal barriers and continued landscape research on B. gargarizans.

scholarly journals Spatial genetic structure and asymmetrical gene flow within the Pacific walrus

2012 ◽  
Vol 93 (6) ◽  
pp. 1512-1524 ◽  
Author(s):  
Sarah A. Sonsthagen ◽  
Chadwick V. Jay ◽  
Anthony S. Fischbach ◽  
George K. Sage ◽  
Sandra L. Talbot
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Spatial Genetic Structure ◽  
Genetic Relationships ◽  
Breeding Population ◽  
Pacific Walrus ◽  
Breeding Populations ◽  
The Pacific

Abstract Pacific walruses (Odobenus rosmarus divergens) occupying shelf waters of Pacific Arctic seas migrate during spring and summer from 3 breeding areas in the Bering Sea to form sexually segregated nonbreeding aggregations. We assessed genetic relationships among 2 putative breeding populations and 6 nonbreeding aggregations. Analyses of mitochondrial DNA (mtDNA) control region sequence data suggest that males are distinct among breeding populations (ΦST = 0.051), and between the eastern Chukchi and other nonbreeding aggregations (ΦST = 0.336–0.449). Nonbreeding female aggregations were genetically distinct across marker types (microsatellite FST = 0.019; mtDNA ΦST = 0.313), as was eastern Chukchi and all other nonbreeding aggregations (microsatellite FST = 0.019–0.035; mtDNA ΦST = 0.386–0.389). Gene flow estimates are asymmetrical from St. Lawrence Island into the southeastern Bering breeding population for both sexes. Partitioning of haplotype frequencies among breeding populations suggests that individuals exhibit some degree of philopatry, although weak. High levels of genetic differentiation among eastern Chukchi and all other nonbreeding aggregations, but considerably lower genetic differentiation between breeding populations, suggest that at least 1 genetically distinct breeding population remained unsampled. Limited genetic structure at microsatellite loci between assayed breeding areas can emerge from several processes, including male-mediated gene flow, or population admixture following a decrease in census size (i.e., due to commercial harvest during 1880–1950s) and subsequent recovery. Nevertheless, high levels of genetic diversity in the Pacific walrus, which withstood prolonged decreases in census numbers with little impact on neutral genetic diversity, may reflect resiliency in the face of past environmental challenges.

scholarly journals Patterns of spatial genetic structures in Aedes albopictus (Diptera: Culicidae) populations in China

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Yong Wei ◽  
Jiatian Wang ◽  
Zhangyao Song ◽  
Yulan He ◽  
Zihao Zheng ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Gene Flow ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Population Genetic ◽  
Spatial Genetic Structure ◽  
Vector Borne Diseases ◽  
Vector Borne ◽  
Genetic Structures

Abstract Background The Asian tiger mosquito, Aedes albopictus, is one of the 100 worst invasive species in the world and the vector for several arboviruses including dengue, Zika and chikungunya viruses. Understanding the population spatial genetic structure, migration, and gene flow of vector species is critical to effectively preventing and controlling vector-borne diseases. Little is known about the population structure and genetic differentiation of native Ae. albopictus in China. The aim of this study was to examine the patterns of the spatial genetic structures of native Ae. albopictus populations, and their relationship to dengue incidence, on a large geographical scale. Methods During 2016–2018, adult female Ae. albopictus mosquitoes were collected by human landing catch (HLC) or human-bait sweep-net collections in 34 localities across China. Thirteen microsatellite markers were used to examine the patterns of genetic diversity, population structure, and gene flow among native Ae. albopictus populations. The correlation between population genetic indices and dengue incidence was also examined. Results A total of 153 distinct alleles were identified at the 13 microsatellite loci in the tested populations. All loci were polymorphic, with the number of distinct alleles ranging from eight to sixteen. Genetic parameters such as PIC, heterozygosity, allelic richness and fixation index (FST) revealed highly polymorphic markers, high genetic diversity, and low population genetic differentiation. In addition, Bayesian analysis of population structure showed two distinct genetic groups in southern-western and eastern-central-northern China. The Mantel test indicated a positive correlation between genetic distance and geographical distance (R2 = 0.245, P = 0.01). STRUCTURE analysis, PCoA and GLS interpolation analysis indicated that Ae. albopictus populations in China were regionally clustered. Gene flow and relatedness estimates were generally high between populations. We observed no correlation between population genetic indices of microsatellite loci in Ae. albopictus populations and dengue incidence. Conclusion Strong gene flow probably assisted by human activities inhibited population differentiation and promoted genetic diversity among populations of Ae. albopictus. This may represent a potential risk of rapid spread of mosquito-borne diseases. The spatial genetic structure, coupled with the association between genetic indices and dengue incidence, may have important implications for understanding the epidemiology, prevention, and control of vector-borne diseases.

Spatial genetic structure inMilicia excelsa(Moraceae) indicates extensive gene dispersal in a low-density wind-pollinated tropical tree

2009 ◽  
Vol 18 (21) ◽  
pp. 4398-4408 ◽  
Author(s):  
J.-P. BIZOUX ◽  
K. DAÏNOU ◽  
N. BOURLAND ◽  
O. J. HARDY ◽  
M. HEUERTZ ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Spatial Genetic Structure ◽  
Tropical Tree ◽  
Low Density ◽  
Gene Dispersal

scholarly journals Population Genetics and Evolution Analysis Reveal Diversity and Origin of Ammopiptanthus in China.

2021 ◽  
Author(s):  
Guai-qiang Chai ◽  
Yizhong Duan ◽  
Peipei Jiao ◽  
Zhongyu Du ◽  
Furen Kang
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Association Studies ◽  
Natural Populations ◽  
Principal Component ◽  
Nucleotide Polymorphisms ◽  
Future Design ◽  
Ammopiptanthus Nanus ◽  
Genome Wide

Abstract Background：Elucidating and revealing the population genetic structure, genetic diversity and recombination is essential for understanding the evolution and adaptation of species. Ammopiptanthus, which is an endangered survivor from the Tethys in the Tertiary Period, is the only evergreen broadleaf shrub grown in Northwest of China. However, little is known about its genetic diversity and underlying adaptation mechanisms. Results：Here, 111 Ammopiptanthus individuals collected from fifteen natural populations in estern China were analyzed by means of the specific locus amplified fragment sequencing (SLAF-seq). Based on the single nucleotide polymorphisms (SNPs) and insertions and deletions (InDels) detected by SLAF-seq, genetic diversity and markers associated with climate and geographical distribution variables were identified. The results of genetic diversity and genetic differentiation revealed that all fifteen populations showed medium genetic diversity, with PIC values ranging from 0.1648 to 0.3081. AMOVA and Fst indicated that a low genetic differentiation existed among populations. Phylogenetic analysis showed that NX-BG and NMG-DQH of fifteen populations have the highest homology，while the genetic structure analysis revealed that these Ammopiptanthus germplasm accessions were structured primarily along the basis of their geographic collection, and that an extensive admixture occurred in each group. In addition, the genome-wide linkage disequilibrium (LD) and principal component analysis showed that Ammopiptanthus nanus had a more diverse genomic background, and all genetic populations were clearly distinguished, although different degrees of introgression were detected in these groups. Conclusion：Our study could provide guidance to the future design of association studies and the systematic utilization and protection of the genetic variation characterizing the Ammopiptanthus.

Staying close: short local dispersal distances on a managed forest of two Patagonian Nothofagus species

2020 ◽  
Vol 93 (5) ◽  
pp. 652-661 ◽  
Author(s):  
Georgina Sola ◽  
Verónica El Mujtar ◽  
Leonardo Gallo ◽  
Giovanni G Vendramin ◽  
Paula Marchelli
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Spatial Genetic Structure ◽  
Pollen Dispersal ◽  
Dispersal Distance ◽  
Restricted Gene Flow ◽  
Fine Scale ◽  
Gene Dispersal ◽  
Mature Trees ◽  
The Impact

Abstract Understanding the impact of management on the dispersal potential of forest tree species is pivotal in the context of global change, given the implications of gene flow on species evolution. We aimed to determine the effect of logging on gene flow distances in two Nothofagus species from temperate Patagonian forests having high ecological relevance and wood quality. Therefore, a total of 778 individuals (mature trees and saplings) of Nothofagus alpina and N. obliqua, from a single plot managed 20 years ago (2.85 hectares), were mapped and genotyped at polymorphic nuclear microsatellite loci. Historical estimates of gene dispersal distance (based on fine-scale spatial genetic structure) and contemporary estimates of seed and pollen dispersal (based on spatially explicit mating models) were obtained. The results indicated restricted gene flow (gene distance ≤ 45 m, both pollen and seed), no selfing and significant seed and pollen immigration from trees located outside the studied plot but in the close surrounding area. The size of trees (diameter at breast height and height) was significantly associated with female and/or male fertility. The significant fine-scale spatial genetic structure was consistent with the restricted seed and pollen dispersal. Moreover, both estimates of gene dispersal (historical and contemporary) gave congruent results. This suggests that the recent history of logging within the study area has not significantly influenced on patterns of gene flow, which can be explained by the silviculture applied to the stand. The residual tree density maintained species composition, and the homogeneous spatial distribution of trees allowed the maintenance of gene dispersal. The short dispersal distance estimated for these two species has several implications both for understanding the evolution of the species and for defining management, conservation and restoration actions. Future replication of this study in other Nothofagus Patagonian forests would be helpful to validate our conclusions.

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