scholarly journals Genome-wide genotyping elucidates the geographical diversification and dispersal of the polyploid and clonally propagated yam (Dioscorea alata)

2020 ◽  
Vol 126 (6) ◽  
pp. 1029-1038
Author(s):  
Bilal Muhammad Sharif ◽  
Concetta Burgarella ◽  
Fabien Cormier ◽  
Pierre Mournet ◽  
Sandrine Causse ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Pool ◽  
Genotyping By Sequencing ◽  
Caribbean Region ◽  
Gene Pools ◽  
Dioscorea Alata ◽  
Allele Frequency Distribution ◽  
Low Genetic Diversity ◽  
Genome Wide ◽  
Greater Yam

Abstract Background and Aims Inferring the diffusion history of many human-dispersed species is still not straightforward due to unresolved past human migrations. The centre of diversification and routes of migration of the autopolyploid and clonally propagated greater yam, Dioscorea alata, one of the oldest edible tubers, remain unclear. Here, we address yam demographic and dispersal history using a worldwide sample. Methods We characterized genome-wide patterns of genetic variation using genotyping by sequencing 643 greater yam accessions spanning four continents. First, we disentangled the polyploid and clonal components of yam diversity using allele frequency distribution and identity by descent approaches. We then addressed yam geographical origin and diffusion history with a model-based coalescent inferential approach. Key Results Diploid genotypes were more frequent than triploids and tetraploids worldwide. Genetic diversity was generally low and clonality appeared to be a main factor of diversification. The most likely evolutionary scenario supported an early divergence of mainland Southeast Asian and Pacific gene pools with continuous migration between them. The genetic make-up of triploids and tetraploids suggests that they have originated from these two regions before westward yam migration. The Indian Peninsula gene pool gave origin to the African gene pool, which was later introduced to the Caribbean region. Conclusions Our results are congruent with the hypothesis of independent domestication origins of the two main Asian and Pacific gene pools. The low genetic diversity and high clonality observed suggest a strong domestication bottleneck followed by thousands of years of widespread vegetative propagation and polyploidization. Both processes reduced the extent of diversity available for breeding, and this is likely to threaten future adaptation.

scholarly journals Population structure, genetic diversity and genomic selection signatures among a Brazilian common bean germplasm

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jessica Delfini ◽  
Vânia Moda-Cirino ◽  
José dos Santos Neto ◽  
Paulo Maurício Ruas ◽  
Gustavo César Sant’Ana ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Common Bean ◽  
Gene Pool ◽  
Association Studies ◽  
Genotyping By Sequencing ◽  
Gene Pools ◽  
Genome Wide Association Studies ◽  
Mesoamerican Gene Pool ◽  
Diversity Panel

AbstractBrazil is the world's largest producer of common bean. Knowledge of the genetic diversity and relatedness of accessions adapted to Brazilian conditions is of great importance for the conservation of germplasm and for directing breeding programs aimed at the development of new cultivars. In this context, the objective of this study was to analyze the genetic diversity, population structure, and linkage disequilibrium (LD) of a diversity panel consisting of 219 common bean accessions, most of which belonging to the Mesoamerican gene pool. Genotyping by sequencing (GBS) of these accessions allowed the identification of 49,817 SNPs with minor allele frequency > 0.05. Of these, 17,149 and 12,876 were exclusive to the Mesoamerican and Andean pools, respectively, and 11,805 SNPs could differentiate the two gene pools. Further the separation according to the gene pool, bayesian analysis of the population structure showed a subdivision of the Mesoamerican accessions based on the origin and color of the seed tegument. LD analysis revealed the occurrence of long linkage blocks and low LD decay with physical distance between SNPs (LD half decay in 249 kb, corrected for population structure and relatedness). The GBS technique could effectively characterize the Brazilian common bean germplasms, and the diversity panel used in this study may be of great use in future genome-wide association studies.

Marked differences in genetic diversity and differentiation between the centre and edge of the geographical range of Megaleranthis saniculifolia (Ranunculaceae), a Korean endemic species

2012 ◽  
Vol 60 (7) ◽  
pp. 582
Author(s):  
Ji Hee Jeong ◽  
Zin-Suh Kim
Keyword(s):  
Genetic Diversity ◽  
Peripheral Region ◽  
Issr Markers ◽  
Ex Situ ◽  
Allele Frequency Distribution ◽  
Low Genetic Diversity ◽  
Long Time ◽  
Megaleranthis Saniculifolia ◽  
Degree Of Differentiation ◽  
Substantial Degree

The amount and distribution of genetic diversity within and between Megaleranthis saniculifolia Ohwi populations were compared between the central and peripheral regions of the species distribution. Allozyme and ISSR markers were used for genetic analysis of six populations from the central region (DY) and five populations from the peripheral region (MJ). Genetic diversity was substantially higher in the DY region than in the MJ region. Relatively uniform homozygote excess at many loci in most populations indicated that M. saniculifolia was influenced by a substantial degree of inbreeding in both regions. The degree of differentiation between populations was remarkably higher in the MJ region than in the DY region. Cluster analysis showed a trend towards separation between regions, although populations in the MJ region exhibited a slightly different trend according to the markers. We conclude that genetic drift has been affecting the populations in the MJ region for a long time, on the basis of their low genetic diversity, high differentiation, U-shaped allele-frequency distribution, and fixation of alleles towards opposing frequencies (1 or 0) among populations. In contrast, the DY region maintained relatively stable populations, although evidence of a recent bottleneck was found in one population. Along with some practical measures for genetic conservation, we present an optimal sample size for ex situ conservation to secure as many common alleles as possible.

scholarly journals Comparing the Effectiveness of Exome Capture Probes, Genotyping by Sequencing and Whole-Genome Re-Sequencing for Assessing Genetic Diversity in Natural and Managed Stands of Picea abies

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1185
Author(s):  
Helena Eklöf ◽  
Carolina Bernhardsson ◽  
Pär K. Ingvarsson
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Picea Abies ◽  
Norway Spruce ◽  
Large Scale ◽  
Genotyping By Sequencing ◽  
Complexity Reduction ◽  
Exome Capture ◽  
Genome Wide ◽  
Targeted Capture

Conifer genomes are characterized by their large size and high abundance of repetitive material, making large-scale genotyping in conifers complicated and expensive. One of the consequences of this is that it has been difficult to generate data on genome-wide levels of genetic variation. To date, researchers have mainly employed various complexity reduction techniques to assess genetic variation across the genome in different conifer species. These methods tend to capture variation in a relatively small subset of a typical conifer genome and it is currently not clear how representative such results are. Here we take advantage of data generated in the first large-scale re-sequencing effort in Norway spruce and assess how well two commonly used complexity reduction methods, targeted capture probes and genotyping by sequencing perform in capturing genome-wide variation in Norway spruce. Our results suggest that both methods perform reasonably well for assessing genetic diversity and population structure in Norway spruce (Picea abies (L.) H. Karst.). Targeted capture probes were slightly more effective than GBS, likely due to them targeting known genomic regions whereas the GBS data contains a substantially greater fraction of repetitive regions, which sometimes can be problematic for assessing genetic diversity. In conclusion, both methods are useful for genotyping large numbers of samples and they greatly reduce the cost involved with genotyping a species with such a complex genome as Norway spruce.

Genetic diversity of Colombian landraces of common bean as detected through the use of silver-stained and fluorescently labelled microsatellites

2011 ◽  
Vol 9 (01) ◽  
pp. 86-96 ◽  
Author(s):  
Lucy M. Díaz ◽  
Héctor F. Buendía ◽  
Myriam C. Duque ◽  
Matthew W. Blair
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Microsatellite Markers ◽  
Common Bean ◽  
Gene Pool ◽  
Major Gene ◽  
Gene Pools ◽  
Silver Stain ◽  
Fluorescent Marker ◽  
Fluorescent Markers

Colombia, situated at the northern end of the Andes mountains of South America and in proximity to Central America, is an important centre of diversity for common bean (Phaseolus vulgarisL.) that has a mix of cultivated germplasm from both major gene pools (Andean and Mesoamerican) for the species. Microsatellites are a useful marker system for analyzing genetic diversity of this crop and can be analyzed with manual (silver-stain) or automated (ABI) detection systems and using unlabelled or fluorescently labelled markers, respectively. The objectives of this research were to evaluate the genetic diversity of 92 Colombian landraces and gene pool controls with 36 fluorescent and 30 non-fluorescent microsatellite markers and to determine the extent of introgression between the Andean and Mesoamerican gene pools for this germplasm. A comparison of fluorescentversusnon-fluorescent marker systems was performed with 14 loci, which were evaluated with both methods; the fluorescent markers were found to be more precise than the non-fluorescent markers in determining population structure. A combined analysis of 52 microsatellites using the 36 fluorescent markers and 16 non-overlapping, silver-stained markers produced an accurate population structure for the Andean gene pool that separated race Nueva Granada and race Peru genotypes and clearly identified introgression between these races and the gene pools. The results of this research are important for the application of microsatellite markers to diversity analysis in common bean and for the conservation of landraces in Colombia and neighbouring countries of Latin America, where similar germplasm exists and where gene pool or race mixtures also occur.

RFLP diversity of common bean (Phaseolus vulgaris) in its centres of origin

Genome ◽  
1994 ◽  
Vol 37 (2) ◽  
pp. 256-263 ◽  
Author(s):  
Viviana L. Becerra Velasquez ◽  
Paul Gepts
Keyword(s):  
Genetic Diversity ◽  
Phaseolus Vulgaris ◽  
Common Bean ◽  
Restriction Fragment ◽  
Fragment Length ◽  
Gene Pool ◽  
Geographical Area ◽  
Rflp Markers ◽  
Gene Pools ◽  
Restriction Fragment Length

Eighty-five wild and cultivated accessions of common bean (Phaseolus vulgaris L.), representing a wide geographic area in the centres of domestication were tested for restriction fragment length polymorphisms (RFLPs). Genomic DNA was digested with one of three restriction enzymes (EcoRI, EcoRV, and HindIII) and hybridized to 12 probes distributed throughout the common bean genome. Accessions could be classified into two major groups with a distinct geographical distribution in Middle America and the Andes. Within each gene pool, cultivated accessions clustered together with wild forms from the same geographical area supporting the multiple domestications hypothesis for this crop. Estimates of Nei's genetic distances among the cultivated races from the two different gene pools varied from 0.12 to 0.56 and among races from the same gene pool from 0.04 to 0.12, suggesting that the divergence in Phaseolus vulgaris has reached the subspecies level. The level of genetic diversity (Ht = 0.38) was twice the value obtained with isozyme analysis. Genetic diversity within races (Hs = 0.27) was four to five times higher compared with isozymes, but genetic diversity between races (Dst = 0.11) was similar for both categories of markers. These results corroborate previous studies on the characterization of genetic diversity in common bean that clearly showed two distinct gene pools, Middle American and Andean. Moreover, RFLP markers are superior to isozymes because they provide better coverage of the genome and reveal higher level of polymorphisms.Key words: common bean, restriction fragment length polymorphism, domestication, genetic diversity.

scholarly journals Genetic characterization of buckwheat accessions through genome-wide allele frequency fingerprints / Genetska karakterizacija vzorcev ajde z odtisi frekvence alelov v genomu

2020 ◽  
Vol 61 (1) ◽  
pp. 17-23
Author(s):  
Michelle M. Nay ◽  
Stephen L. Byrne ◽  
Eduardo A. Pérez ◽  
Achim Walter ◽  
Bruno Studer
Keyword(s):  
Genetic Diversity ◽  
Single Nucleotide Polymorphisms ◽  
Allele Frequency ◽  
Genotyping By Sequencing ◽  
Allele Frequencies ◽  
Fagopyrum Esculentum ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Genome Wide ◽  
Fagopyrum Esculentum Moench

Genomics-assisted breeding of buckwheat (Fagopyrum esculentum Moench) depends on robust genotyping methods. Genotyping by sequencing (GBS) has evolved as a flexible and cost-effective technique frequently used in plant breeding. Several GBS pipelines are available to genetically characterize single genotypes but these are not able to represent the genetic diversity of buckwheat accessions that are maintained as genetically heterogeneous, open-pollinating populations. Here we report the development of a GBS pipeline which, rather than reporting the state of bi-allelic single nucleotide polymorphisms (SNPs), resolves allele frequencies within populations on a genome-wide scale. These genome-wide allele frequency fingerprints (GWAFFs) from 100 pooled individual plants per accession were found to be highly reproducible and revealed the genetic similarity of 20 different buckwheat accessions analysed in our study. The GWAFFs cannot only be used as an efficient tool to precisely describe buckwheat breeding material, they also offer new opportunities to investigate the genetic diversity between different buckwheat accessions and establish variant databases for key material. Furthermore, GWAFFs provide the opportunity to associate allele frequencies to phenotypic traits and quality parameters that are most reliably described on population level. This is the key to practically implement powerful genomics-assisted breeding concepts such as marker-assisted selection and genomic selection in future breeding schemes of allogamous buckwheat. Key words: Buckwheat (Fagopyrum esculentum Moench), genotyping by sequencing (GBS), population genomics, genome-wide allele frequency fingerprints (GWAFFs)   Izvleček Genomsko podprto žlahtnjenje ajde (Fagopyrum esculentum Moench) je odvisno od robustnih metod genotipiziranja. Genotipiziranje s spremljanjem sekvenc (genotyping by sequencing, GBS) se je razvilo kot fleksibilna in razmeroma poceni metoda, ki se jo uporablja pri žlahtnjenju rastlin. Uporabnih je več virov GBS za genetsko karakterizacijo posamičnih genotipov, toda te metode niso primerne za predstavitev genetske raznolikosti vzorcev ajde, ki jih vzdržujemo v heterozigotni obliki, kar velja za odprto oplodne populacije. Tu poročamo o razvoju GBS metode, ki, namesto prikazovanja bi-alelnega polimorfizma posameznih nukleotidov (single nucleotide polymorphisms, SNPs), pokaže frekvence alelov v populaciji na nivoju genoma. Ta prikaz frekvence alelov na nivoju genoma (genome-wide allele frequency fingerprints, GWAFFs) z združenimi sto posameznimi rastlinami vsakega vzorca se je pokazal kot visoko ponovljiv in je prikazal genetsko podobnost 20 različnih vzorcev ajde, ki smo jih analizirali v naši raziskavi. Metoda GWAFFs ni uporabna samo kot učinkovito orodje za natančen opis materiala za žlahtnjenje ajde, ponuja tudi možnosti raziskave  genetskih razlik med različnimi vzorci ajde in omogoča zbirke podatkov. Nadalje, metoda GWAFFs omogoča povezovanje frekvenc alelov s fenotipskimi lastnostmi in kvalitativnih parametrov, ki so najbolj zanesljivo opisani na nivoju populacij. To je ključ za praktično uporabo z genomiko podprtega žlahtnjenja, kot je z genskimi markerji podprta selekcija in genomska selekcija z GWAFFs. Ključne besede: ajda (Fagopyrum esculentum Moench), genotipizacija s sekvenciranjem (GBS), populacijska genomika, GWAFFs

scholarly journals Populations of Phytophthora rubi Show Little Differentiation and High Rates of Migration Among States in the Western United States

2018 ◽  
Vol 31 (6) ◽  
pp. 614-622 ◽  
Author(s):  
Javier F. Tabima ◽  
Michael D. Coffey ◽  
Inga A. Zazada ◽  
Niklaus J. Grünwald
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Root Rot ◽  
Genotyping By Sequencing ◽  
The United States ◽  
Western United States ◽  
Lineage Sorting ◽  
Phytophthora Root Rot ◽  
Agricultural Ecosystems ◽  
Low Genetic Diversity

Population genetics is a powerful tool to understand patterns and evolutionary processes that are involved in plant-pathogen emergence and adaptation to agricultural ecosystems. We are interested in studying the population dynamics of Phytophthora rubi, the causal agent of Phytophthora root rot in raspberry. P. rubi is found in the western United States, where most of the fresh and processed raspberries are produced. We used genotyping-by-sequencing to characterize genetic diversity in populations of P. rubi sampled in the United States and other countries. Our results confirm that P. rubi is a monophyletic species with complete lineage sorting from its sister taxon P. fragariae. Overall, populations of P. rubi show low genetic diversity across the western United States. Demographic analyses suggest that populations of P. rubi from the western United States are the source of pathogen migration to Europe. We found no evidence for population differentiation at a global or regional (western United States) level. Finally, our results provide evidence of migration from California and Oregon into Washington. This report provides new insights into the evolution and structure of global and western United States populations of the raspberry pathogen P. rubi, indicating that human activity might be involved in moving the pathogen among regions and fields.

scholarly journals Employing Genome-Wide SNP Discovery to Characterize the Genetic Diversity in Cinnamomum camphora Using Genotyping by Sequencing

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1511
Author(s):  
Xue Gong ◽  
Aihong Yang ◽  
Zhaoxiang Wu ◽  
Caihui Chen ◽  
Huihu Li ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
East Asia ◽  
Japanese Population ◽  
Eastern China ◽  
Genotyping By Sequencing ◽  
Central China ◽  
Western China ◽  
Cinnamomum Camphora ◽  
Ecological Value ◽  
Genome Wide

Cinnamomum camphora (L.) J.Presl is a representative tree species of evergreen broad-leafed forests in East Asia and has exceptionally high economic, ornamental, and ecological value. However, the excessive exploitation and utilization of C. camphora trees have resulted in the shrinking of wild population sizes and rare germplasm resources. In this study, we characterized 171 C. camphora trees from 39 natural populations distributed throughout the whole of China and one Japanese population. We investigated genetic diversity and population structure using genome-wide single-nucleotide polymorphism (SNP) identified by genotyping by sequencing (GBS) technology. The results showed the genetic diversity of the C. camphora populations from western China > central China > eastern China. Moreover, the Japanese population showed the highest diversity among all populations. The molecular variance analysis showed 92.03% of the genetic variation within populations. The average pairwise FST was 0.099, and gene flow Nm was 2.718, suggesting a low genetic differentiation among populations. Based on the genetic clustering analysis, the 40 C. camphora populations clustered into three major groups: Western China, Central China, and Eastern China + Japan. Eastern China’s population had the closest genetic relationship with the Japanese population, suggesting possible gene exchange between the two adjacent areas. This study furthers our understanding of the genetic diversity and genetic structure of C. camphora in East Asia and provides genetic tools for developing strategies of C. camphora germplasm utilization.

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