scholarly journals Pervasive hybridizations in the history of wheat relatives

2019 ◽  
Vol 5 (5) ◽  
pp. eaav9188 ◽  
Author(s):  
Sylvain Glémin ◽  
Celine Scornavacca ◽  
Jacques Dainat ◽  
Concetta Burgarella ◽  
Véronique Viader ◽  
...  
Keyword(s):  
Methodological Approach ◽  
Diploid Species ◽  
Phylogenomic Analysis ◽  
D Genome ◽  
B Genome ◽  
Hybridization Event ◽  
History Of ◽  
Complex Scenario ◽  
Ancient Hybridization

Cultivated wheats are derived from an intricate history of three genomes, A, B, and D, present in both diploid and polyploid species. It was recently proposed that the D genome originated from an ancient hybridization between the A and B lineages. However, this result has been questioned, and a robust phylogeny of wheat relatives is still lacking. Using transcriptome data from all diploid species and a new methodological approach, our comprehensive phylogenomic analysis revealed that more than half of the species descend from an ancient hybridization event but with a more complex scenario involving a different parent than previously thought—Aegilops mutica, an overlooked wild species—instead of the B genome. We also detected other extensive gene flow events that could explain long-standing controversies in the classification of wheat relatives.

scholarly journals Pervasive hybridizations in the history of wheat relatives

2018 ◽  
Author(s):  
Sylvain Glémin ◽  
Celine Scornavacca ◽  
Jacques Dainat ◽  
Concetta Burgarella ◽  
Véronique Viader ◽  
...  
Keyword(s):  
Methodological Approach ◽  
Diploid Species ◽  
Phylogenomic Analysis ◽  
D Genome ◽  
Species Relationship ◽  
B Genome ◽  
Hybridization Event ◽  
A Genome ◽  
History Of ◽  
Complex Scenario

AbstractBread wheat and durum wheat derive from an intricate evolutionary history of three genomes, namely A, B and D, present in both extent diploid and polyploid species. Despite its importance for wheat research, no consensus on the phylogeny of the wheat clade has emerged so far, possibly because of hybridizations and gene flows that make phylogeny reconstruction challenging. Recently, it has been proposed that the D genome originated from an ancient hybridization event between the A and B genomes1. However, the study only relied on four diploid wheat relatives when 13 species are accessible. Using transcriptome data from all diploid species and a new methodological approach, we provide the first comprehensive phylogenomic analysis of this group. Our analysis reveals that most species belong to the D-genome lineage and descend from the previously detected hybridization event, but with a more complex scenario and with a different parent than previously thought. If we confirmed that one parent was the A genome, we found that the second was not the B genome but the ancestor of Aegilops mutica (T genome), an overlooked wild species. We also unravel evidence of other massive gene flow events that could explain long-standing controversies in the classification of wheat relatives. We anticipate that these results will strongly affect future wheat research by providing a robust evolutionary framework and refocusing interest on understudied species. The new method we proposed should also be pivotal for further methodological developments to reconstruct species relationship with multiple hybridizations.

Variability in wheat based on low-copy DNA sequence comparisons

Genome ◽  
1995 ◽  
Vol 38 (5) ◽  
pp. 951-957 ◽  
Author(s):  
L. E. Talbert ◽  
N. K. Blake ◽  
E. W. Storlie ◽  
M. Lavin
Keyword(s):  
Dna Sequence ◽  
Diploid Species ◽  
Sequence Variability ◽  
D Genome ◽  
Sequence Comparisons ◽  
Molecular Analyses ◽  
B Genome ◽  
Hybridization Event ◽  
Copy Dna ◽  
Diploid Ancestor

The chromosomes of the B genome of hexaploid wheat (AABBDD) do not pair completely with those of any of the diploid species with genomes similar to B. Various biochemical and molecular analyses have suggested that each of the five diploid species in section Sitopsis of Triticum are ancestral to B. These observations have led to the hypothesis that the B genome may be polyphyletic, descending from more than one diploid ancestor. This hypothesis may account for differences between the wheat B genome and the diploids and also for variability that currently exists among different wheat accessions. In this study, we cloned and compared nucleotide sequences for three low-copy DNA fragments from the B and D genomes of several wheat accessions and from diploid relatives of the B and D genomes. Our results suggested that the amount of DNA sequence variability in wheat is low, although somewhat more variability existed in the B genome than in the D genome. The B genome of wheat was significantly diverged from all the Sitopsis diploid species, and Triticum speltoides was closer to B than to other members of this section. The D genome of wheat was very similar to that of its progenitor, Triticum tauschii. No evidence for a polyphyletic origin of the B genome was found. A more parsimonious hypothesis is that the wheat B genome diverged from its diploid ancestor after the original hybridization event occurred.Key words: wheat, low-copy DNA, phylogenetics.

scholarly journals Insights on the process of reciprocal gene loss in the duplicate DPL genes of rice

2019 ◽  
Author(s):  
Xun Xu ◽  
Song Ge ◽  
Fu-min Zhang
Keyword(s):  
Evolutionary History ◽  
Gene Loss ◽  
Diploid Species ◽  
Recent Common Ancestor ◽  
Duplicate Genes ◽  
Evolutionary Divergence ◽  
Dna Transposons ◽  
B Genome ◽  
A Genome ◽  
History Of

Abstract Background: Reciprocal gene loss (RGL) of duplicate genes is an important genetic resource of reproductive isolation, which is essential for speciation. In the past decades, various RGL patterns have been revealed, but RGL process is still poorly understood. The RGL of the duplicate DOPPELGANGER1 (DPL1) and DOPPELGANGER2 (DPL2) gene can lead to BDM-type hybrid incompatibility between two rice subspecies. The evolutionary history of the duplicate genes, including their origin and mechanism of duplication as well as their evolutionary divergence after the duplication, remains unclear. In this study, we investigated the evolutionary history of the duplicate genes for gaining insights into the process of RGL.Results: We reconstructed phylogenetic relationships of DPL copies from all 15 diploid species representing six genome types of rice genus and then found that all the DPL copies from the latest diverged A- and B-genome gather into one monophyletic clade. Southern blot analysis also detected definitely two DPL copies only in A- and B-genome. High conserved collinearity can be observed between A- and B-genomic segments containing DPL1 and DPL2 respectively but not between DPL1 and DPL2 segments. Investigations of transposon elements indicated that DPL duplication is related to DNA transposons. Likelihood-based analyses with branch models showed a relaxation of selective constraint in DPL1 lineage but an enhancement in DPL2 lineage after DPL duplication. Sequence analysis also indicated that quite a few defective DPL1 can be found in 6 wild and cultivated species out of all 8 species of A-genome but only one defective DPL2 occurs in a cultivated rice subspecies. Conclusions: DPL duplication of rice originated in the recent common ancestor of A- and B-genome about 6.76 million years ago and the duplication was possibly caused by DNA transposons. The DPL1 is a redundant copy and has being in the process of pseudogenization, suggesting that artificial selection may play an important role in forming the RGL of DPLs between two rice subspecies during the domestication.

Molecular evidence for the origin and evolution of chromosome 4A in polyploidy wheats

1985 ◽  
Vol 27 (2) ◽  
pp. 246-250 ◽  
Author(s):  
A. Lane Rayburn ◽  
B. S. Gill
Keyword(s):  
In Situ Hybridization ◽  
Chinese Spring ◽  
Diploid Species ◽  
Aegilops Speltoides ◽  
Molecular Evidence ◽  
Wheat Evolution ◽  
D Genome ◽  
Origin And Evolution ◽  
B Genome

The chromosomes of polyploid Triticum species and the putative donor diploid species were analyzed by in situ hybridization with a repeated DNA sequence clone pSc 119 isolated from rye and also found in wheat. In Triticum aestivum cv. Chinese Spring, chromosome 4A showed one terminal site in the short arm and one terminal and two interstitial sites of hybridization in the long arm. Triticum turgidum contained a 4A chromosome identical to 'Chinese Spring' with respect to hybridization sites. Chromosome 4A of the timopheevi wheats differed from 4A of 'Chinese Spring' in that the site of the sequence on the short arm was subterminal rather than terminal. Of the A-, B-, and D-genome progenitor species, only potential B-genome donors Aegilops speltoides and Aegilops sharonensis each showed a chromosome with hybridization sites similar to 4A. This suggested that 4A belongs to the B genome. Moreover, with regard to this sequence, chromosome 4A has undergone only minor changes during the evolution of the polyploid wheats.Key words: wheat evolution, in situ hybridization, biotin labeling.

scholarly journals Identification of RAPD markers linked to A and B genome sequences in Musa L.

Genome ◽  
2000 ◽  
Vol 43 (5) ◽  
pp. 763-767 ◽  
Author(s):  
M Pillay ◽  
D C Nwakanma ◽  
A Tenkouano
Keyword(s):  
Rapd Markers ◽  
Rapd Analysis ◽  
Random Amplified Polymorphic Dna ◽  
Diploid Species ◽  
Morphological Characteristics ◽  
Genome Composition ◽  
Reliable System ◽  
B Genome ◽  
Wild Diploid Species

Plantains and bananas (Musa spp. sect. eumusa) originated from intra- and interspecific hybridization between two wild diploid species, M. acuminata Colla. and M. balbisiana Colla., which contributed the A and B genomes, respectively. Polyploidy and hybridization have given rise to a number of diploid, triploid, and tetraploid clones with different permutations of the A and B genomes. Thus, dessert and highland bananas are classified mainly as AAA, plantains are AAB, and cooking bananas are ABB. Classification of Musa into genomic groups has been based on morphological characteristics. This study aimed to identify RAPD (random amplified polymorphic DNA) markers for the A and B genomes. Eighty 10-mer Operon primers were used to amplify DNA from M. acuminata subsp. burmannicoides clone 'Calcutta 4' (AA genomes) and M. balbisiana clone 'Honduras' (BB genomes). Three primers (A17, A18, and D10) that produced unique genome-specific fragments in the two species were identified. These primers were tested in a sample of 40 genotypes representing various genome combinations. The RAPD markers were able to elucidate the genome composition of all the genotypes. The results showed that RAPD analysis can provide a quick and reliable system for genome identification in Musa that could facilitate genome characterization and manipulations in breeding lines.Key words: banana and plantain, A and B genomes, genomic groups, RAPD markers.

To Understand the Informal (on the Book BY V. L. Tambovtsev “Economics of Informal Institutions”)

2015 ◽  
pp. 151-158
Author(s):  
A. Zaostrovtsev
Keyword(s):  
Social Psychology ◽  
Detailed Analysis ◽  
Human Behavior ◽  
Interdisciplinary Approach ◽  
Informal Institutions ◽  
Economic Thought ◽  
History Of ◽  
Original Classification

The review considers the first attempt in the history of Russian economic thought to give a detailed analysis of informal institutions (IF). It recognizes that in general it was successful: the reader gets acquainted with the original classification of institutions (including informal ones) and their genesis. According to the reviewer the best achievement of the author is his interdisciplinary approach to the study of problems and, moreover, his bias on the achievements of social psychology because the model of human behavior in the economic mainstream is rather primitive. The book makes evident that namely this model limits the ability of economists to analyze IF. The reviewer also shares the author’s position that in the analysis of the IF genesis the economists should highlight the uncertainty and reject economic determinism. Further discussion of IF is hardly possible without referring to this book.

Diversification of the North American Doellingeria-Eucephalus Clade (Astereae: Asteraceae) Inferred from Molecular and Morphological Evidence

2019 ◽  
Vol 44 (4) ◽  
pp. 930-942
Author(s):  
Geraldine A. Allen ◽  
Luc Brouillet ◽  
John C. Semple ◽  
Heidi J. Guest ◽  
Robert Underhill
Keyword(s):  
North American ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Sister Group ◽  
Morphological Evidence ◽  
South American ◽  
New Combinations ◽  
The North ◽  
Hybridization Event ◽  
Ancient Hybridization

Abstract—Doellingeria and Eucephalus form the earliest-diverging clade of the North American Astereae lineage. Phylogenetic analyses of both nuclear and plastid sequence data show that the Doellingeria-Eucephalus clade consists of two main subclades that differ from current circumscriptions of the two genera. Doellingeria is the sister group to E. elegans, and the Doellingeria + E. elegans subclade in turn is sister to the subclade containing all remaining species of Eucephalus. In the plastid phylogeny, the two subclades are deeply divergent, a pattern that is consistent with an ancient hybridization event involving ancestral species of the Doellingeria-Eucephalus clade and an ancestral taxon of a related North American or South American group. Divergence of the two Doellingeria-Eucephalus subclades may have occurred in association with northward migration from South American ancestors. We combine these two genera under the older of the two names, Doellingeria, and propose 12 new combinations (10 species and two varieties) for all species of Eucephalus.

Assessment criteria for aggregate social welfare

2020 ◽  
Vol 19 (12) ◽  
pp. 2358-2371
Author(s):  
S.A. Moskal'onov
Keyword(s):  
Social Welfare ◽  
Mathematical Analysis ◽  
Exchange Economy ◽  
Assessment Criteria ◽  
Impossibility Theorem ◽  
New Approaches ◽  
History Of Development ◽  
Arrow's Impossibility Theorem ◽  
History Of

Subject. The article addresses the history of development and provides the criticism of existing criteria for aggregate social welfare (on the simple exchange economy (the Edgeworth box) case). Objectives. The purpose is to develop a unique classification of criteria to assess the aggregate social welfare. Methods. The study draws on methods of logical and mathematical analysis. Results. The paper considers strong, strict and weak versions of the Pareto, Kaldor, Hicks, Scitovsky, and Samuelson criteria, introduces the notion of equivalence and constructs orderings by Pareto, Kaldor, Hicks, Scitovsky, and Samuelson. The Pareto and Samuelson's criteria are transitive, however, not complete. The Kaldor, Hicks, Scitovsky citeria are not transitive in the general case. Conclusions. The lack of an ideal social welfare criterion is the consequence of the Arrow’s Impossibility Theorem, and of the group of impossibility theorems in economics. It is necessary to develop new approaches to the assessment of aggregate welfare.

COLLECTING THE PERSONAL ORIGIN DOCUMENTS OF THE GREAT PATRIOTIC WAR PERIOD

2020 ◽  
pp. 97-114
Author(s):  
Elena M. Burova ◽  
Keyword(s):  
Research Literature ◽  
Home Front ◽  
Organization Of Work ◽  
Great Patriotic War ◽  
History Of ◽  
Ordinary Citizens

The article covers the issues of initiative acquisition of archives in the documents of personal origin during the Great Patriotic War, the organization of work to identify and collect the wartime documents. Collecting documents of ordinary citizens, in particular letters from the front and to the front is analyzed. Proposals to create the specialized archives of documents on the history of the war were never implemented. Quite a lot of the actions, search operations and expeditions were conducted in the country, for example, the “Chronicle of the Great Patriotic War”, the “Frontline letter”, the “Search”, the “Memory”, etc., during which a significant number of documents of war participants and home front workers were collected and stored. Not so much of the documents of personal origin of the war participants are concentrated in the archives. In general, there prevails the collection type of organization for storing documents from the period of the Great Patriotic War. With reference to the corpus of documents of personal origin of the war period the research literature pays its attention mostly to correspondence and diaries, memoirs. Historians and archivists, analyzing wartime letters, offer different classifications depending on the authors, recipients, subjects, etc. The article provides a generalized classification of letters based on their inherent similarities. The author also analyzes the reasons for a small number of extant diaries and memoirs, and provides examples of their classification. Likewise the article describes current approaches to the collection of personal papers within the frames of the Moscow Glavarkhiv project “Moscow – with care for history” and the Ministry of Defense project “The Memory Road”.

(A review). BRAUN-BLANQUETIA. Recueil de travaux de geobotanique / review of geobotanical monographs. Vol. 46. Centenaire de la phytosociologie. CAMERINO, 2010. 423 p.

2011 ◽  
pp. 143-147
Author(s):  
L. G. Naumova ◽  
V. B. Martynenko ◽  
S. M. Yamalov
Keyword(s):  
Plant Association ◽  
Northern Asia ◽  
The Third ◽  
International Botanical ◽  
International Botanical Congress ◽  
History Of ◽  
Definition Of

Date of «birth» of phytosociology (phytocenology) is considered to be 1910, when at the third International Botanical Congress in Brussels adopted the definition of plant association in the wording Including Flaó and K. Schröter (Flahault, Schröter, 1910; Alexandrov, 1969). The centenary of this momentous event in the history of phytocenology devoted to the 46th edition of the Yearbook «Braun-Blanquetia», which began to emerge in 1984 in Camerino (Italy) and it has a task to publish large geobotanical works. During the years of the publication of the Yearbook on its pages were published twice work of the Russian scientists — «The steppes of Mongolia» (Z. V. Karamysheva, V. N. Khramtsov. Vol. 17. 1995), and «Classification of continental hemiboreal forests of Northern Asia» (N. B. Ermakov in collaboration with English colleagues and J. Dring, J. Rodwell. Vol. 28. 2000).

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