scholarly journals Genetic diversity and population structure of rice stripe virus in China

2009 ◽  
Vol 90 (4) ◽  
pp. 1025-1034 ◽  
Author(s):  
Tai-Yun Wei ◽  
Jin-Guang Yang ◽  
Fu-Long Liao ◽  
Fang-Luan Gao ◽  
Lian-Ming Lu ◽  
...  

Rice stripe virus (RSV) is one of the most economically important pathogens of rice and is repeatedly epidemic in China, Japan and Korea. The most recent outbreak of RSV in eastern China in 2000 caused significant losses and raised serious concerns. In this paper, we provide a genotyping profile of RSV field isolates and describe the population structure of RSV in China, based on the nucleotide sequences of isolates collected from different geographical regions during 1997–2004. RSV isolates could be divided into two or three subtypes, depending on which gene was analysed. The genetic distances between subtypes range from 0.050 to 0.067. The population from eastern China is composed only of subtype I/IB isolates. In contrast, the population from Yunnan province (southwest China) is composed mainly of subtype II isolates, but also contains a small proportion of subtype I/IB isolates and subtype IA isolates. However, subpopulations collected from different districts in eastern China or Yunnan province are not genetically differentiated and show frequent gene flow. RSV genes were found to be under strong negative selection. Our data suggest that the most recent outbreak of RSV in eastern China was not due to the invasion of new RSV subtype(s). The evolutionary processes contributing to the observed genetic diversity and population structure are discussed.

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Yu-Hua Fu ◽  
Chenglong Yang ◽  
Qiuyi Meng ◽  
Fanzhi Liu ◽  
Gang Shen ◽  
...  

Coix lacryma-jobi L. is an important minor cereal with a high nutritional and medicinal value in Asian countries. The hilly region of South China is the secondary center of diversity of Coix lacryma-jobi L. In the present study, we took a sample of 139 Coix lacryma-jobi L. genotypes from four geographical regions in Southwest China and analyzed the genetic diversity and population structure using AFLP markers. Six primer combinations detected a total of 743 (89.52%) polymorphic loci. The percentage of polymorphic bands within the four geographical populations ranged from 56.02% (Guangxi) to 86.75% (Guizhou). The overall genetic diversity of 139 Coix lacryma-jobi L. was relatively low (h ranged from 0.1854 to 0.2564). The neighbor-joining method grouped all Coix lacryma-jobi L. genotypes into two clusters with no geographical affinity observed among genotypes within the same group. The Fst indicated the two clusters existed great genetic differentiation. AMOVA analysis showed the molecular variation within populations was much higher than that among populations of geographical regions and subpopulations derived from STRUCTURE. Human activities and the natural outcrossing system of Coix lacryma-jobi L. may have a great influence on its distribution, genetic diversity, and population structure. Our study provides useful information for local breeding programs of Coix lacryma-jobi L. as well.


2021 ◽  
Vol 12 ◽  
Author(s):  
Tian-Qi Shi ◽  
Hai-Mo Shen ◽  
Shen-Bo Chen ◽  
Kokouvi Kassegne ◽  
Yan-Bing Cui ◽  
...  

Malaria incidence has declined dramatically over the past decade and China was certified malaria-free in 2021. However, the presence of malaria in border areas and the importation of cases of malaria parasites are major challenges for the consolidation of the achievements made by China. Plasmodium vivax Duffy binding protein (PvDBP) performs a significant role in erythrocyte invasion, and is considered a promising P. vivax vaccine. However, the highly polymorphic region of PvDBP (PvDBP-II) impedes the development of blood-stage vaccine against P. vivax. In this study, we investigated the genetic diversity and natural selection of PvDBP-II among 124 P. vivax isolates collected from the China-Myanmar border (CMB) in Yunnan Province, China, during 2009–2011. To compare genetic diversity, natural selection, and population structure with CMB isolates, 85 pvdbp-II sequences of eastern Myanmar isolates were obtained from GenBank. In addition, global sequences of pvdbp-II were retrieved from GenBank to establish genetic differentiation relationships and networks with the CMB isolates. In total, 22 single nucleotide polymorphisms reflected in 20 non-synonymous and two synonymous mutations were identified. The overall nucleotide diversity of PvDBP-II from the 124 CMB isolates was 0.0059 with 21 haplotypes identified (Hd = 0.91). The high ratio of non-synonymous to synonymous mutations suggests that PvDBP-II had evolved under positive selection. Population structure analysis of the CMB and eastern Myanmar isolates were optimally grouped into five sub-populations (K = 5). Polymorphisms of PvDBP-II display that CMB isolates were genetically diverse. Mutation, recombination, and positive selection promote polymorphism of PvDBP-II of P. vivax population. Although low-level genetic differentiation in eastern Myanmar was identified along with the more effective malaria control measures, the complexity of population structure in malaria parasites has maintained. In conclusion, findings from this study advance knowledge of the understanding of the dynamic of P. vivax population, which will contribute to guiding the rational design of a PvDBP-II based vaccine.


2009 ◽  
Vol 45 (No. 4) ◽  
pp. 155-159 ◽  
Author(s):  
X.Z. Liu ◽  
C.S. He ◽  
Y.M. Yang ◽  
H.Y. Zhang

AFLP analyses were used to assess the genetic similarity among selected accessions at the South China Tobacco Breeding Research Centre (Yunnan province, Southwest China). 154 AFLP polymorphic fragments out of 561 fragments were used to assess the genetic diversity among 28 tobacco accessions. The average number of polymorphic bands per AFLP primer pair was 15.4. AFLPs seemed to be an effective classification tools for germplasm conservation and breeding. Limited genetic variation was detected within this group of accessions. The relationship of cultivars was estimated by cluster analysis based on AFLP data.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Salvatore Bordonaro ◽  
Anna Maria Guastella ◽  
Andrea Criscione ◽  
Antonio Zuccaro ◽  
Donata Marletta

The genetic variability of Pantesco and other two Sicilian autochthonous donkey breeds (Ragusano and Grigio Siciliano) was assessed using a set of 14 microsatellites. The main goals were to describe the current differentiation among the breeds and to provide genetic information useful to safeguard the Pantesco breed as well as to manage Ragusano and Grigio Siciliano. In the whole sample, that included 108 donkeys representative of the three populations, a total of 85 alleles were detected. The mean number of alleles was lower in Pantesco (3.7), than in Grigio Siciliano and Ragusano (4.4 and 5.9, resp.). The three breeds showed a quite low level of gene diversity (He) ranging from 0.471 in Pantesco to 0.589 in Grigio. The overall genetic differentiation index (Fst) was quite high; more than 10% of the diversity was found among breeds. Reynolds’ () genetic distances, correspondence, and population structure analysis reproduced the same picture, revealing that, (a) Pantesco breed is the most differentiated in the context of the Sicilian indigenous breeds, (b) within Ragusano breed, two well-defined subgroups were observed. This information is worth of further investigation in order to provide suitable data for conservation strategies.


PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0253600
Author(s):  
Charles U. Uba ◽  
Happiness O. Oselebe ◽  
Abush A. Tesfaye ◽  
Wosene G. Abtew

Understanding the genetic structure and diversity of crops facilitates progress in plant breeding. A collection of 270 bambara groundnut (Vigna subterrenea L) landraces sourced from different geographical regions (Nigeria/Cameroon, West, Central, Southern and East Africa) and unknown origin (sourced from United Kingdom) was used to assess genetic diversity, relationship and population structure using DArT SNP markers. The major allele frequency ranged from 0.57 for unknown origin to 0.91 for West Africa region. The total gene diversity (0.482) and Shannon diversity index (0.787) was higher in West African accessions. The genetic distance between pairs of regions varied from 0.002 to 0.028 with higher similarity between Nigeria/Cameroon-West Africa accessions and East-Southern Africa accessions. The analysis of molecular variance (AMOVA) revealed 89% of genetic variation within population, 8% among regions and 3% among population. The genetic relatedness among the collections was evaluated using neighbor joining tree analysis, which grouped all the geographic regions into three major clusters. Three major subgroups of bambara groundnut were identified using the ADMIXTURE model program and confirmed by discriminant analysis of principal components (DAPC). These subgroups were West Africa, Nigeria/Cameroon and unknown origin that gave rise to sub-population one, and Central Africa was sub-population two, while Southern and East Africa were sub-population three. In general, the results of all the different analytical methods used in this study confirmed the existence of high level of diversity among the germplasm used in this study that might be utilized for future genetic improvement of bambara groundnut. The finding also provides new insight on the population structure of African bambara groundnut germplasm which will help in conservation strategy and management of the crop.


Author(s):  
Muhammet Fatih Aydin ◽  
Faheem Shehzad Baloch

Present study was aimed to investigate the genetic diversity and population structure of Turkish common bean germplasm. A total of 96 bean genotypes were characterized with iPBS-retrotansposons that yielded a mean polymorphism information contents of 0.8. Mean gene diversity and Shannon information index were 0.14 and 0.25, respectively. Neighbor joining analysis divided the bean genotypes into two main group (A and B) according to their geographical regions, growth habits and seed size. Bingol-l7, Sivas-14 and Hakkari-11 genotypes were found very distinct and can be used as candidate parents for the bean breeding. The higher efficiency and reproducibility of iPBS-retrotransposons was witnessed in common bean as compared to earlier studies using the same marker system. Results of this study will boost up the investigators for genotyping the larger germplasm of common bean with minimum laboratory infrastructure in developing and least developed countries.


1998 ◽  
Vol 76 (3) ◽  
pp. 500-508 ◽  
Author(s):  
Om P Rajora ◽  
Linda DeVerno ◽  
Alex Mosseler ◽  
David J Innes

The dramatic decline of eastern white pine (Pinus strobus L.) populations in Newfoundland over the past 100 years presents an opportunity to determine and monitor population bottleneck effects on genetic diversity in trees. To provide benchmarks and indicators for monitoring genetic changes due to recent and future bottleneck events and to assist development of conservation strategies, we assessed genetic diversity and structure of six small, isolated white pine populations from two regions at the limits of its geographical range in Newfoundland for comparison with three populations from its central range in Ontario for 20 allozyme loci coding for 12 enzymes. On average, 47.8% of the loci were polymorphic, the number of alleles per locus was 1.75, and the observed and expected heterozygosities were 0.215 and 0.195, respectively. Although most of the alleles were widespread, unique alleles were found in three of the nine populations examined. The Newfoundland populations were as genetically variable as those from Ontario. Generally, all populations exhibited slight excess of heterozygotes at most loci. Only 6.1% of the detected genetic variation was among populations, and the remainder among individuals within populations. The genetic distances among the populations within a province or region were as great as those among populations between the provinces or regions. Canonical discriminant functions and cluster analysis from genetic distances separated nine populations into the same four groups. Neither provincial nor regional or geographic gradient-related patterns of population variation and differentiation were apparent. It appears that 8000 years of postglacial geographic isolation and recent population decline have had little or no detectable effect on genetic diversity or differentiation of disjunct Newfoundland white pine populations from their ancestral mainland populations. Assuming their adaptability, the Ontario seed sources may be acceptable for white pine restoration in Newfoundland.Key words : Pinus strobus, allozymes, gene conservation, genetic diversity and population structure, genetic drift, population bottleneck.


2020 ◽  
Vol 51 (6) ◽  
pp. 611-619
Author(s):  
Adrian Medina-Montes ◽  
Darwin Hernández-Herrera ◽  
Javier Beltrán-Herrera ◽  
Donicer Montes-Vergara

The objective of this study was to evaluate the genetic diversity of the Colombian Creole donkey in the Department of Sucre using Random Amplified Microsatellites (RAM) molecular markers. In 100 individuals from the five subregions of the department, DNA was extracted and five RAM primers were amplified by PCR. In all, 291 bands were found, on average 11.96±1.45 per primer, the highest value in CCA (18±2.23) and the lowest in TG and GT (8.8±0.44). CA was the most polymorphic primer (88.09±10.91%) with the highest heterozygosity value (He) (0.376±0.021), while the lowest was GT (0.341±0.076 and 0.101±0.040, respectively). Intrapopulation analysis showed an average of 66.50±1.72 bands, of which 89.86±24.04% were polymorphic. The highest number of bands (63±3.84) was found in the Gulf of Morrosquillo (GO) subpopulation, and the lowest in Mojana (MO) (48±2.88); however, the highest value of polymorphic loci (81.16%) and He (0.335±0.022) were found in the Montes de María (MM) subpopulation, making it the most diverse. The average genetic diversity for the entire population was 0.351±0.021 bands. The population structure analysis showed a 10% variation between subpopulations, with an FST value of 0.17±0.01 (P<0.05). Genetic distances between subpopulations showed that MO and GO were the most distant. The RAM markers are effective in assessing the genetic diversity of the Creole donkey, which has high values of genetic diversity, particularly the MM subpopulation. The genetic revealed structure could be the result of natural geographical barriers between the subregions.


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