scholarly journals Distinct Genetic Structure Reflects Ploidy Level Differentiation in Newly Discovered, Extremely Small Populations of Xanthocyparis vietnamensis from Southwestern China

2021 ◽  
Vol 12 ◽  
Author(s):  
Yuliang Jiang ◽  
Tsam Ju ◽  
Linda E. Neaves ◽  
Jialiang Li ◽  
Weining Tan ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Endangered Species ◽  
Genetic Differentiation ◽  
Ploidy Level ◽  
Population Genetic ◽  
Ex Situ ◽  
Southwestern China ◽  
Small Populations ◽  
Population Groups ◽  
Quaternary Climate

Population genetic assessment is crucial for the conservation and management of threatened species. Xanthocyparis vietnamensis is an endangered species that is currently restricted to karst mountains in southwestern China and Vietnam. This rare conifer was first recorded in 2002 from northern Vietnam and then in 2013 from Guangxi, China, yet nothing is known about its genetic diversity nor ploidy level variation, although previous cytological study suggest that Vietnamese populations are tetraploids. There have been about 45 individuals found to date in Guangxi, China. Here, we genotyped 33 X. vietnamensis individuals using 20 newly developed, polymorphic microsatellite loci, to assess the genetic variability of its extremely small populations. The genetic diversity of X. vietnamensis (HE = 0.511) was lower than that of two other heliophile species, Calocedrus macrolepis and Fokienia hodginsii, which have similar distribution ranges. This is consistent with the signature of a genetic bottleneck detected in X. vietnamensis. Although the population genetic differentiation coefficient across loci is moderate (FST = 0.125), STRUCTURE analysis revealed two distinct genetic clusters, namely the northern and southern population groups; DAPC analysis grouped the southern populations together in one cluster separate from the northern populations; AMOVA analysis detected a significant genetic differentiation between the two population groups (FRT = 0.089, p < 0.05), and BARRIER analysis detected a genetic barrier between them. Moreover, we detected differentiation in ploidy level between northern and southern populations, sampled individuals from the former and the later are all diploid and tetraploid cytotypes with mean genome sizes of 26.08 and 48.02 pg/2C, respectively. We deduced that heterogeneous geomorphology and historical events (e.g., human deforestation, Quaternary climate oscillations) may have contributed to population fragmentation and small population size in X. vietnamensis. Considering both genetic and ploidy level differentiation, we propose that two different management units (northern and southern) should be considered and a combination of in situ and ex situ conservation measures should be employed to preserve populations of this endangered species in southwestern China in the light of our findings.

The population genetic structure and diversification of Aristolochia delavayi (Aristolochiaceae), an endangered species of the dry hot valleys of the Jinsha River, southwestern China

Botany ◽  
2014 ◽  
Vol 92 (8) ◽  
pp. 579-587 ◽  
Author(s):  
Zhi-Yun Yang ◽  
Ting-Shuang Yi ◽  
Liang-Qin Zeng ◽  
Xun Gong
Keyword(s):  
Genetic Diversity ◽  
Endangered Species ◽  
Population Size ◽  
Gene Diversity ◽  
Issr Markers ◽  
Habitat Destruction ◽  
Ex Situ ◽  
Southwestern China ◽  
Jinsha River ◽  
Genetic Diversity And Structure

Aristolochia delavayi Franch. is an endangered species of the dry hot valleys of the Jinsha River, southwestern China. The genetic diversity and structure of the species and the occurrence of gene flow were investigated with eight inter-simple sequence repeat (ISSR) markers and four plastid loci (matK, trnL-trnT, rps4-trnT, and trnC-rpoB). The analysis of ISSR markers indicated that the genetic diversity of the species is relatively high (PPB = 84.71%). Similarly, a high gene diversity of HT = 0.833 was found based on the four plastid loci. It is possible that this species previously maintained a large effective population size and that the current relict distribution of the species is a result of large-scale fragmentation and habitat destruction. The origin of the species at approximately 3.407 million years ago and the ensuing intraspecific divergence are generally consistent with the history of two major glaciations in this region. Conservation measures are urgently needed to increase the genetic diversity and population size of this species through both in- and ex-situ action.

scholarly journals Genetic Diversity and Population Genetic Structure of Erythrophleum fordii Oliv., an Endangered Rosewood Species in South China

Forests ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 636 ◽  
Author(s):  
Jing Tan ◽  
Zhi-Gang Zhao ◽  
Jun-Jie Guo ◽  
Chun-Sheng Wang ◽  
Jie Zeng
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Endangered Species ◽  
Genetic Differentiation ◽  
South China ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
The Mean ◽  
Erythrophleum Fordii ◽  
Private Alleles

Erythrophleum fordii Oliv. is a valuable rosewood species indigenous to the tropical and warm sub-tropical zones of Vietnam, Laos, and South China. The natural forests have been heavily fragmented mostly due to over-exploitation and over-utilization, and alteration to croplands and fast-growing plantations. Therefore, it has been included in the IUCN Red List of Endangered Species as an endangered species. In the present study, genetic diversity and population genetic structure of 11 populations were estimated by SSR makers in South China. Five high polymorphic loci were studied with a total of 34 alleles, among which, seven were private alleles. The mean number of alleles per locus (A), the mean number of efficient alleles per locus (Ae), the observed (Ho) and expected (He) heterozygosity, and Shannon’s index (I) of the 11 populations were 3.40, 2.31, 0.52, 0.56, and 0.90, respectively. Correlation analysis between genetic parameters and geographical factors showed that He and I were in significant negative correlation with longitude, indicating that genetic diversity of E. fordii reduced gradually from West to East in south China. FIS of eight populations with above five samples was on average 0.01, most loci conformed to Hardy-Weinberg equilibrium in these populations; their genetic differentiation coefficient (FST) was 0.18, indicating that genetic differentiation among populations was relatively low and there existed 18% genetic variation among populations. Gene flow (Nm) between these populations was 1.28. The Mantel test showed that genetic distance was not significantly correlated with geographical distance (p > 0.05). It was concluded that populations with high genetic diversity or private alleles, especially Longmen, Wuming and Pingxiang populations should be a priority for in situ conservations, meanwhile more populations and as many families as possible in each population should be collected for ex situ conservations of germplasm resources of this species in the future.

scholarly journals Genetic diversity and population structure of the narrow endemic and endangered species Heteroplexis microcephala Y. L. Chen. in China revealed by random amplified polymorphic DNA markers

2016 ◽  
Vol 68 (3) ◽  
pp. 669-675
Author(s):  
Yancai Shi ◽  
Xiao Wei ◽  
Jiqing Wei ◽  
Yongtao Li ◽  
Shengfeng Chai ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Endangered Species ◽  
Genetic Differentiation ◽  
Dna Markers ◽  
Gene Diversity ◽  
Random Amplified Polymorphic Dna ◽  
Population Level ◽  
Dispersal Distance ◽  
Ex Situ

Heteroplexis microcephala Y. L. Chen. is an endemic and endangered species found only in karst limestone regions in the Yangshuo County of the Guangxi Zhuang Autonomous Region in China: it is a habitat representative of species in the Heteroplexis genus. To provide basic genetic information for its conservation, in this study we evaluated the genetic variation and differentiation among six wild populations of H. microcephala by random amplified polymorphic DNA markers (RAPD). The leaves of 141 individuals were sampled. Based on 12 primers, 113 DNA fragments were generated. Genetic diversity was low at the population level (Nei?s gene diversity (h)=0.0579; Shannon information index (I)=0.0924; percentage of polymorphic bands (PPB)=23.30%), but relatively high at the species level (h=0.1701; I=0.2551; PPB=46.34%). The coefficient of genetic differentiation based on Nei?s genetic diversity analysis (0.6661) was high, indicating that there was significant genetic differentiation among populations, which was confirmed by AMOVA analysis exhibiting population differentiation among populations of 68.77%. Low gene flow among populations (0.2507) may result from several factors, such as a harsh pollination environment, population isolation and low seed dispersal distance. Limited gene flow and self-compatibility are the primary reasons for the high genetic differentiation observed for this species. We propose the collection of seeds from more populations with fewer individuals and core populations for ex situ conservation and suggest methods to increase seed germination rates.

Population genetics and conservation of the critically endangered Clematis acerifolia (Ranunculaceae)

2005 ◽  
Vol 83 (10) ◽  
pp. 1248-1256 ◽  
Author(s):  
J. López-Pujol ◽  
F.-M. Zhang ◽  
S. Ge
Keyword(s):  
Genetic Diversity ◽  
Population Genetic ◽  
Critically Endangered ◽  
Ex Situ ◽  
Genetic Structuring ◽  
Long Term Storage ◽  
Hardy Weinberg Equilibrium ◽  
Term Storage

Allozyme electrophoresis was used to evaluate the levels of genetic diversity and population genetic structure of the critically endangered Clematis acerifolia Maximowicz (Ranunculaceae), a narrow endemic species in China. On the basis of variation at 19 putative loci in nine populations covering the entire distribution of this species, low values of genetic diversity were detected (P = 20.5%, A = 1.27, and He = 0.072). A significant deficiency of heterozygotes was found in all populations. Most loci showed deviations from the Hardy–Weinberg equilibrium, probably as a result of population genetic structuring. The high genetic divergence among populations (FST = 0.273) can be interpreted as an effect of the extinction of local populations and genetic drift within extant populations, and has probably been enhanced by habitat fragmentation in recent decades. Threats to this species are mainly anthropogenic (road works, construction of holiday resorts, and extraction activities), although stochastic risks cannot be ignored. Therefore, to preserve extant genetic variation of C. acerifolia, in situ strategies, such as the preservation of its habitat or at least the most diverse populations, and ex situ measures, such as the collection and long-term storage of seeds, should be adopted.

scholarly journals Non-linear genetic diversity and notable population differentiation caused by low gene flow of bermudagrass [Cynodon dactylon (L.) Pers.] along longitude gradients

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11953
Author(s):  
Jing-Xue Zhang ◽  
Miaoli Wang ◽  
Jibiao Fan ◽  
Zhi-Peng Guo ◽  
Yongzhuo Guan ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Gene Flow ◽  
Genetic Distance ◽  
Ploidy Level ◽  
Population Genetic ◽  
Annual Precipitation ◽  
Mean Annual Precipitation ◽  
Ploidy Levels ◽  
Population Genetic Diversity

Background Environmental variation related to ecological habitat is the main driver of plant adaptive divergence. Longitude plays an important role in the formation of plant population structure, indicating that environmental differentiation can significantly shape population structure. Methods Genetic diversity and population genetic structure were estimated using 105 expressed sequence tag-derived simple sequence repeat (EST-SSR) loci. A total of 249 C. dactylon (L.) Pers. (common bermudagrass) individuals were sampled from 13 geographic sites along the longitude (105°57′34″–119°27′06″E). Results There was no obvious linear trend of intra-population genetic diversity along longitude and the intra-population genetic diversity was not related to climate in this study. Low gene flow (Nm = 0.7701) meant a rich genetic differentiation among populations of C. dactylon along longitude gradients. Significantly positive Mantel correlation (r = 0.438, P = 0.001) was found between genetic distance and geographical interval while no significant partial Mantel correlation after controlling the effect of mean annual precipitation, which indicated geographic distance correlated with mean annual precipitation affect genetic distance. The genetic diversity of C. dactylon with higher ploidy level was higher than that with lower ploidy level and groups of individuals with higher ploidy level were separated further away by genetic distance from the lower ploidy levels. Understanding the different genetic bases of local adaptation comparatively between latitude and longitude is one of the core findings in the adaptive evolution of plants.

scholarly journals Ocean Currents Drove Genetic Structure of Seven Dominant Mangrove Species Along the Coastlines of Southern China

2021 ◽  
Vol 12 ◽  
Author(s):  
Qifang Geng ◽  
Zhongsheng Wang ◽  
Jianmin Tao ◽  
Megumi K. Kimura ◽  
Hong Liu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
South China ◽  
Population Genetic ◽  
Ocean Currents ◽  
Mangrove Species ◽  
Contemporary Gene Flow ◽  
Low Levels ◽  
Oceanic Currents

Mangrove forest ecosystems, which provide important ecological services for marine environments and human activities, are being destroyed worldwide at an alarming rate. The objective of our study was to use molecular data and analytical techniques to separate the effects of historical and contemporary processes on the distribution of mangroves and patterns of population genetic differentiation. Seven mangrove species (Acanthus ilicifolius, Aegiceras corniculatum, Avicennia marina, Bruguiera gymnorrhiza, Kandelia obovata, Lumnitzera racemosa, and Rhizophora stylosa), which are predominant along the coastlines of South China, were genotyped at nuclear (nSSR) and chloroplast (cpSSR) microsatellite markers. We estimated historical and contemporary gene flow, the genetic diversity and population structure of seven mangrove species in China. All of these seven species exhibited few haplotypes, low levels of genetic diversity (HE = 0.160–0.361, with the exception of K. obovata) and high levels of inbreeding (FIS = 0.104–0.637), which may be due to their marginal geographical distribution, human-driven and natural stressors on habitat loss and fragmentation. The distribution patterns of haplotypes and population genetic structures of seven mangrove species in China suggest historical connectivity between populations over a large geographic area. In contrast, significant genetic differentiation [FST = 0.165–0.629 (nSSR); GST = 0.173–0.923 (cpSSR)] indicates that populations of mangroves are isolated from one another with low levels of contemporary gene flow among populations. Our results suggest that populations of mangroves were historically more widely inter-connected and have recently been isolated, likely through a combination of ocean currents and human activities. In addition, genetic admixture in Beibu Gulf populations and populations surrounding Hainan Island and southern mainland China were attributed to asymmetric gene flow along prevailing oceanic currents in China in historical times. Even ocean currents promote genetic exchanges among mangrove populations, which are still unable to offset the effects of natural and anthropogenic fragmentation. The recent isolation and lack of gene flow among populations of mangroves may affect their long-term survival along the coastlines of South China. Our study enhances the understanding of oceanic currents contributing to population connectivity, and the effects of anthropogenic and natural habitat fragmentation on mangroves, thereby informing future conservation efforts and seascape genetics toward mangroves.

scholarly journals Genetic diversity and population structure of Eurycoma apiculata in Eastern Sumatra, Indonesia

2021 ◽  
Vol 22 (10) ◽  
Author(s):  
Zulfahmi Zulfahmi ◽  
Parjanto Parjanto ◽  
Edi Purwanto ◽  
Ahmad Yunus
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Variation ◽  
Genetic Differentiation ◽  
Gene Diversity ◽  
In Situ Conservation ◽  
Genetic Material ◽  
Ex Situ ◽  
Breeding Programs ◽  
The Mean

Abstract. Zulfahmi, Parjanto, Purwanto E, Yunus A. 2021. Genetic diversity and population structure of Eurycoma apiculata in Eastern Sumatra, Indonesia. Biodiversitas 22: 4431-4439. Information on genetic variation within and among populations of Eurycoma apiculata plants is important to develop strategies for their conservation, sustainable use, and genetic improvement. To date, no information on genetic variation within and among populations of the E. apiculata has been reported. This study aims to assess genetic diversity within and among populations of E. apiculata based on RAPD markers, and to determine populations to collect E. apiculata genetic material for conservation and breeding programs. Young leaves of E. apiculata were collected from six natural populations. Fifteen RAPD primers were used to assess the genetic diversity of each population. The data obtained were analyzed with POPGEN and Arlequin software. The amplification results of 15 selected primers produced 3-16 loci with all primers 100% polymorphic. At the species level, the mean allele per locus (Na), number of effective alleles (Ne), percentage of polymorphic loci (PPL), Nei’s gene diversity index (He) and Shannon information index (I) were 2.000, 1.244, 100%, 0.167, and 0.286, respectively. At the population level, the mean values for Na, Ne, PPL, He and I were 1.393, 1.312, 39.27%, 0.119, and 0.186, respectively. The highest value of gene diversity within population (He) was found in the Lingga-1 population and the lowest value was found in the Rumbio population. The value of genetic differentiation among populations (GST) of E. apiculata is 0.284, consistent with the results of the AMOVA analysis which found that genetic variation among populations was 23.14%, indicates that the genetic variation of E. apiculata was more stored within populations than among populations. The gene flow (Nm) value of E. apiculata was 1.259 migrants per generation among populations. The Nm value of this species was high category, and could inhibit genetic differentiation among populations. The clustering of E. apiculata population based on the UPGMA dendrogram and PCA was inconsistent with its geographic distribution, reflecting the possibility that genes migration occurred between islands in the past. The main finding of this study was the genetic variation of the E. apiculata mostly stored within the population. Therefore, the population with the highest genetic diversity is a priority for in-situ conservation, and collection of E. apiculata genetic material for ex-situ conservation and breeding programs should be carried out minimum from Lingga-1 and Pokomo populations.

scholarly journals Population Genetic Analysis of Pinus Koraiensis in China Inferred Using EST-SSR Markers

2020 ◽  
Author(s):  
Xiang Li ◽  
Minghui Zhao ◽  
Yujin Xu ◽  
Yan Li ◽  
Mulualem Tigabu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Differentiation ◽  
Population Genetic ◽  
Association Studies ◽  
Genetic Erosion ◽  
Conservation Strategies ◽  
Distribution Area ◽  
Pinus Koraiensis ◽  
Genome Wide Association Studies ◽  
Conifer Species

Abstract Background Pinus koraiensis (commonly known as Korean pine), is a well-known conifer species in China with high economic, ornamental and ecological values. More than 50% of the P. koraiensis forests in the world are distributed in Northeast China, a region with abundant germplasm resources. However, these natural P. koraiensis populations are in danger of genetic erosion caused by continuous climate changes and frequent human activity. Little work has been conducted on the population genetic structure and genetic differentiation of P. koraiensis in China. Here, representative individuals from 16 natural P. koraiensis populations were sampled and genotyped, and polymorphic expressed sequence tag-simple sequence repeat (EST-SSR) markers were used to comprehensively evaluate genetic diversity, population structure and differentiation of P. koraiensis populations in China.ResultsA total of 480 samples from 16 populations were collected in the natural distribution area of P. koraiensis. Analysis of molecular variance (AMOVA) of the EST-SSR marker data showed that 33% of the total genetic variation was among populations and 67% was within populations. A high level of genetic diversity was found across P. koraiensis populations (average Na=10.33, Ne=2.514, He=0.521), and the highest levels of genetic diversity were found in Heihe (He=0.449), Zhanhe (He=0.413), Liangshui (He=0.370) and Tieli (He=0.414) populations. Moreover, pairwise Fst values reveled significant genetic differentiation among populations (mean Fst=0.177). Structure and Neighbor-joining (NJ) tree analyses and principal component analysis (PCA) revealed two genetic clusters: cluster 1 from Xiaoxinganling Mountains and cluster 2 from Changbaishan Mountains, which were consistent with the geographical distributions of the natural populations. ConclusionsThe findings provide new genetic information for future genome-wide association studies (GWAS), marker-assisted selection (MAS) and genomic selection (GS) in natural P. koraiensis breeding programs and can aid the development of conservation strategies for this valuable conifer species.

scholarly journals Conservation of genetic diversity in Mediterranean endemic species: Arenaria balearica (Caryophyllaceae)

2020 ◽  
Vol 153 (3) ◽  
pp. 348-360
Author(s):  
Javier Bobo-Pinilla ◽  
Noemí López-González ◽  
Julio Peñas
Keyword(s):  
Genetic Diversity ◽  
Endangered Species ◽  
Endemic Species ◽  
Ex Situ Conservation ◽  
Molecular Techniques ◽  
Ex Situ ◽  
Disjunct Distribution ◽  
The Mediterranean ◽  
Rocky Habitats

Background – Biodiversity loss is a problem that needs to be urgently addressed, particularly with the uncertainties of climate change. Current conservation policies principally focus on endangered species but they often give little consideration to the evolutionary processes, genetic diversity, or the rarity of non-endangered species. Endemic species occurring in rocky habitats that are undergoing exceptional habitat loss appear to be one of the most important candidates for conservation. The aim is to establish in situ and ex situ conservation recommendations for the Mediterranean endemic species Arenaria balearica.Material and methods – Arenaria balearica is a species endemic to the Mediterranean with a disjunct distribution range throughout Majorca, Corsica, Sardinia, and other small Tyrrhenian islands. A combination of molecular techniques (AFLPs and plastid DNA) was employed to determine genetic diversity and rarity across populations and to calculate the Relevant Genetic Units for Conservation (RGUCs). Moreover, Species Distribution Models (SDMs) were developed to assess the potential current distribution and the expected situation under future climatic scenarios.Key results – To preserve the genetic diversity and rarity of the species, in situ conservation is proposed for six populations as RGUCs. Moreover, as the RGUCs can only account for a part of the phylogeographic signal, ex situ conservation is also suggested for some additional populations. According to the results, the habitat suitability in the 2050 scenario is limited and suitable areas for A. balearica could have disappeared by 2070. Therefore, the persistence of the species could be in danger in a short period of time and conservation planning becomes necessary.

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