Genome relationship between Thinopyrum bessarabicum and T. elongatum: revisited

Genome ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 802-809 ◽  
Author(s):  
Richard R.-C. Wang ◽  
Catherine Hsiao
Keyword(s):  
Early Spring ◽  
Meiotic Pairing ◽  
Triploid Plant ◽  
Wide Range ◽  
Close Relationship ◽  
Bivalent Formation ◽  
Thinopyrum Bessarabicum ◽  
Grown Plant ◽  
Unreduced Megaspore ◽  
Metaphase I

New meiotic pairing data on triploids and amphidiploids derived from the diploid hybrids between Thinopyrum bessarabicum (Savul. &Rayss) A. Love (2n = 14; JJ) and T. elongatum (Host) D. R. Dewey (2n = 14; JeJe) are presented, which support the close relationship between the genomes of these two species. Three triploids having the JJJe genome constitution were analyzed. Two (both derived from backcrossing amphidiploids of T. bessarabicum × T. elongatum with T. bessarabicum) had an averaged metaphase I pairing pattern of 3.89 I + 0.96 rod II + 3.30 ring II + 2.75 III + 0.06 chain IV + 0.01 ring IV in spikes from a field-grown plant and two greenhouse-grown plants sampled in early spring. Another, which was the F1 triploid progeny of T. bessarabicum × T. elongatum as the result of fertilization of an unreduced megaspore (JJ) by a reduced microspore (Je), had 3.62 I + 2.16 rod II + 1.34 ring II + 3.28 III + 0.10 chain IV + 0.02 ring IV in spikes of a field-grown plant. The first triploid plant had an averaged metaphase I pairing of 4.60 I + 0.74 rod II + 4.03 ring II + 2.19 III + 0.06 chain IV + 0.01 V in spikes sampled in a warmer greenhouse. The amphidiploids exhibited variable pairing patterns with a wide range of multivalent frequency. It is interpreted that the J and Je genomes are essentially homologous, with difference due mainly to two translocations. A genetic mechanism for a "bivalentization" appeared to be present in most, if not all, amphidiploids and the triploids derived from them. Meiotic pairing patterns reported here for triploid hybrids T. junceiforme (Love &Love) A. Love (2n = 28; JJJeJe) × T. bessarabicum, its reciprocal, and T. bessarabicum × T. scirpeum (K. Presl) D. R. Dewey (2n = 28; JeJeJeJe) also support the conclusion that J and Je genomes are homologous. The network of meiotic data supports the conclusion that J and Je are two versions of the same basic genome.Key words: genome, meiosis, hybrid, amphiploid, bivalent formation.

Genome constitution of the Australian hexaploid grass Elymus scabrus (Poaceae: Triticeae)

Genome ◽  
1993 ◽  
Vol 36 (1) ◽  
pp. 147-151 ◽  
Author(s):  
J. Torabinejad ◽  
R. J. Mueller
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Intergeneric Hybrid ◽  
Meiotic Pairing ◽  
Genome Constitution ◽  
Psathyrostachys Juncea ◽  
Hybrid Plants ◽  
Thinopyrum Bessarabicum ◽  
Mother Cells ◽  
Metaphase I

Eight intergeneric hybrid plants were obtained between Elymus scabrus (2n = 6x = 42, SSYY??) and Australopyrum pectinatum ssp. retrofractum (2n = 2x = 14, WW). The hybrids were vegetatively vigorous but reproductively sterile. Examination of pollen mother cells at metaphase I revealed an average of 16.63 I, 5.29 II, 0.19 III, and 0.05 IV per cell for the eight hybrids. The average chiasma frequency of 6.77 per cell in the above hybrids strongly supports the presence of a W genome from A. pectinatum ssp. retrofractum in E. scabrus. Meiotic pairing data of some other interspecific hybrids suggest the existence of the SY genomes in E. scabrus. Therefore, the genome constitution of E. scabrus should be written as SSYYWW. Two other hybrid plants resulted from Elymus yezoensis (2n = 4x = 28, SSYY) crosses with A. pectinatum ssp. pectinatum (2n = 2x = 14, WW). Both were weak and sterile. An average of 0.45 bivalents per cell were observed at metaphase I. This clearly indicates a lack of pairing between W genome of Australopyrum and S or Y genomes of E. yezoensis. In addition, six hybrid plants of E. scabrus with Psathyrostachys juncea (2n = 2x = 14, NN) and one with Thinopyrum bessarabicum (2n = 2x = 14, JJ) were also obtained. The average bivalents per cell formed in both combinations were 2.84 and 0.70, respectively. The results of the latter two combinations showed that there is no N or J genome in E. scabrus.Key words: wide hybridization, chromosome pairing, genome analysis, Australopyrum, Elymus.

scholarly journals A Brief Overview of Social Network Analysis and its Current State within Romanian Sociology

2013 ◽  
Vol 3 (3) ◽  
pp. 5-11
Author(s):  
Marian-Gabriel Hâncean
Keyword(s):  
Social Network ◽  
Social Network Analysis ◽  
Network Analysis ◽  
International Relations ◽  
Early Spring ◽  
Research Topics ◽  
Political Sciences ◽  
Current State ◽  
Wide Range ◽  
Network Studies

Abstract The field of social network studies has been growing within the last 40 years, gathering scholars from a wide range of disciplines (biology, chemistry, geography, international relations, mathematics, political sciences, sociology etc.) and covering diverse substantive research topics. Using Google metrics, the scientific production within the field it is shown to follow an ascending trend since the late 60s. Within the Romanian sociology, social network analysis is still in his early spring, network studies being low in number and rather peripheral. This note gives a brief overview of social network analysis and makes some short references to the current state of the network studies within Romanian sociology

scholarly journals Quantifying seed production by volunteer canola (Brassica napus) and Sinapis arvensis

2011 ◽  
Vol 29 (3) ◽  
pp. 489-497
Author(s):  
E Soltani ◽  
A Soltani ◽  
S Galeshi ◽  
F Ghaderi-far ◽  
E Zeinali
Keyword(s):  
Brassica Napus ◽  
Seed Production ◽  
Cropping Systems ◽  
Plant Size ◽  
Quantitative Information ◽  
Sinapis Arvensis ◽  
Soil Seed Banks ◽  
Sowing Dates ◽  
Wide Range ◽  
Close Relationship

Volunteer canola (Brassica napus) and Sinapis arvensis are well identified weeds of different cropping systems. Quantitative information on regarding seed production by them is limited. Such information is necessary to model dynamics of soil seed banks. The aim of this work was to quantify seed production as a function of the size of those weeds. A wide range of plant size was produced by using a fan seeding system performed at two sowing dates (environments). Plant size varied from 3 to 167 g per plant for canola and from 6 to 104 g per plant for S. arvensis. Seed production ranged from 543 to14,773 seeds per plant for canola, and from 264 to 10,336 seeds per plant for S. arvensis. There was a close relationship between seed production per plant and plant size which was well-described by a power function (y = 130.6x0.94; R² = 0.93 for canola and y = 28x1.27; R² = 0.95 for S. arvensis). There was also strong relationships among the number of pods produced in individual plants and the quantity of seeds produced (g per plant) with the size of the plant. The relationships found in this study can be used in dynamic seed bank models of volunteer canola and S. arvensis.

scholarly journals One-Dimensional Hydrodynamic Modeling of the Euphrates River and Prediction of Hydraulic Parameters

2020 ◽  
Vol 6 (6) ◽  
pp. 1074-1090
Author(s):  
Nassrin Jassim Hussien Al-Mansori ◽  
Laith Shaker Ashoor Al-Zubaidi
Keyword(s):  
Water Resource ◽  
Gaussian Elimination ◽  
Linear Equations ◽  
Flow Characteristics ◽  
Early Spring ◽  
Future Application ◽  
Hydraulic Parameters ◽  
Euphrates River ◽  
One Dimensional ◽  
Wide Range

Forecasting techniques are essential in the planning, design, and management of water resource systems. The numerical model introduced in this study turns governing differential equations into systems of linear or non-linear equations in the flow field, thereby revealing solutions. This one-dimensional hydrodynamic model represents the varied unsteady flow found in natural channels based on the Saint-Venant Equations. The model consists of the equations for the conservation of mass and momentum, which are recognized as very powerful mathematical tools for studying an important class of water resource problems. These problems are characterized by time dependence of flow and cover a wide range of phenomena. The formulations, held up by the four-point implicit finite difference scheme, solve the nonlinear system of equations using the Newton-Raphson iteration method with a modified Gaussian elimination technique. The model is calibrated using data on the Euphrates River during the early spring flood in 2015. It is verified by its application to an ideal canal and to the reach selected at the Euphrates River; this application is also used to predict the effect of hydraulic parameters on the river’s flow characteristics. A comparison between model results and field data indicates the feasibility of our technique and the accuracy of results (R2 = 0.997), meaning that the model is ready for future application whenever field observations are available. 

scholarly journals CONSERVATIVE PARTY AND THE PROBLEMS OF THE BRITISH EMPIRE IN THE EARLY YEARS OF THE SECOND WORLD WAR (on the pages of “Diary of a diplomat” by I. M. Maisky)

2016 ◽  
pp. 32-37
Author(s):  
E. V. Khakhalkina
Keyword(s):  
British Empire ◽  
Conservative Party ◽  
Second World War ◽  
Early Years ◽  
World War ◽  
Dominant Position ◽  
Wide Range ◽  
Close Relationship ◽  
The Uk ◽  
Second World

The “Diary” of the Soviet diplomat I. M. Maisky, who worked in London for more than ten years first as a messenger, then as the Soviet ambassador to the UK, is one of the valuable sources for the interwar period and the Second World War. The “Diary” contains records of Maisky’s conversations with the leading British politicians and public figures and his own thoughts on a wide range of issues, including the problems of the British Empire. The author of the paper analyzes the views of the Tories on the prospects for the British Empire and the Commonwealth of the postwar period and reveals the plans for the reconstruction of the Empire and its transformation while maintaining the dominant position of Britain in the format of a new relationship with the dominions and colonies. The paper shows that within the British political establishment there was no consensus on the future of the empire and, as the materials of the “Diary of diplomat” evidence, the problem of the evolution of the Empire had a close relationship with other areas of foreign and domestic policy.

scholarly journals Oligopaint DNA FISH as a tool for investigating meiotic chromosome dynamics in the silkworm, Bombyx mori

2021 ◽  
Author(s):  
Leah F Rosin ◽  
Jose Gil ◽  
Ines Anna Drinnenberg ◽  
Elissa P Lei
Keyword(s):  
Bombyx Mori ◽  
Meiotic Chromosome ◽  
Low Cost ◽  
Classical Model ◽  
Spindle Pole ◽  
Meiotic Pairing ◽  
Homolog Pairing ◽  
Bivalent Formation ◽  
High Flexibility ◽  
Silkworm Bombyx Mori

Accurate chromosome segregation during meiosis is essential for reproductive success. Yet, many fundamental aspects of meiosis remain unclear, including the mechanisms regulating homolog pairing across species. This gap is partially due to our inability to visualize individual chromosomes during meiosis. Here, we employ Oligopaint FISH to investigate homolog pairing and compaction of meiotic chromosomes in a classical model system, the silkworm Bombyx mori. Our Oligopaint design combines multiplexed barcoding with secondary oligo labeling for high flexibility and low cost. These studies illustrate that Oligopaints are highly specific in whole-mount gonads and on meiotic chromosome spreads. We show that meiotic pairing is robust in both males and female meiosis. Additionally, we show that meiotic bivalent formation in B. mori males is highly similar to bivalent formation in C. elegans, with both of these pathways ultimately resulting in the pairing of chromosome ends with non-paired ends facing the spindle pole and microtubule recruitment independent of the centromere-specifying factor CENP-A.

scholarly journals Tetrahymena Meiotic Nuclear Reorganization Is Induced by a Checkpoint Kinase–dependent Response to DNA Damage

2009 ◽  
Vol 20 (9) ◽  
pp. 2428-2437 ◽  
Author(s):  
Josef Loidl ◽  
Kazufumi Mochizuki
Keyword(s):  
Dna Damage ◽  
Kinase Inhibitors ◽  
Signal Transduction Pathway ◽  
Dna Lesions ◽  
Meiotic Pairing ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Nuclear Reorganization ◽  
Bivalent Formation ◽  
Atr Kinase

In the ciliate Tetrahymena, meiotic micronuclei (MICs) undergo extreme elongation, and meiotic pairing and recombination take place within these elongated nuclei (the “crescents”). We have previously shown that elongation does not occur in the absence of Spo11p-induced DNA double-strand breaks (DSBs). Here we show that elongation is restored in spo11Δ mutants by various DNA-damaging agents including ones that may not cause DSBs to a notable extent. MIC elongation following Spo11p-induced DSBs or artificially induced DNA lesions is probably a DNA-damage response mediated by a phosphokinase signal transduction pathway, since it is suppressed by the ATM/ATR kinase inhibitors caffeine and wortmannin and by knocking out Tetrahymena's ATR orthologue. MIC elongation occurs concomitantly with the movement of centromeres away from the telomeric pole of the MIC. This DNA damage–dependent reorganization of the MIC helps to arrange homologous chromosomes alongside each other but is not sufficient for exact pairing. Thus, Spo11p contributes to bivalent formation in two ways: by creating a favorable spatial disposition of homologues and by stabilizing pairing by crossovers. The polarized chromosome orientation inside the crescent resembles the conserved meiotic bouquet, and crescent and bouquet also share the putative function of aiding meiotic pairing. However, they are regulated differently because in Tetrahymena, DSBs are required for entering rather than exiting this stage.

The effect of fertilizers and season on the yield and composition of wheat in southern New South Wales

1963 ◽  
Vol 3 (8) ◽  
pp. 51 ◽  
Author(s):  
JD Colwell
Keyword(s):  
Vegetative Growth ◽  
Field Experiments ◽  
Application Rate ◽  
Early Spring ◽  
Nitrogen Fertilizers ◽  
Yield Response ◽  
Nitrogen Levels ◽  
South Wales ◽  
Wide Range ◽  
Common Application

Twenty two fertilizer experiments with wheat were carried out over a wide range of soil and environmental seasonal conditions in southern N.S. W. The effects of phosphorus and nitrogen fertilizers on the yield and composition of wheat are described. Seasonal environmental effects were examined by comparing the relative response to fertilizers of vegetative growth in the early spring with the final response of the harvested grain. Grain yield response to fertilizers is commonly restricted by seasonal conditions. Overcorrection of the phosphorus or nitrogen deficiencies may cause excessive early vegetative growth which exhausts soil moisture reserves before grain development has been completed. Loss of grain yields through this phenomenon is described locally as haying off. The chief danger in this respect seems to be from excessive nitrogen levels in the soil following a clover pasture. Assessments of economically desirable fertilizer applications on the basis of field experiments can only be based on statistical averages of seasonal conditions in each locality. The trials indicate, however, that the common application rate of superphosphate to wheat is inadequate in this region and should be at least doubled.

scholarly journals Simple framework for constructing functional spiking recurrent neural networks

2019 ◽  
Vol 116 (45) ◽  
pp. 22811-22820 ◽  
Author(s):  
Robert Kim ◽  
Yinghao Li ◽  
Terrence J. Sejnowski
Keyword(s):  
Neural Networks ◽  
Recurrent Neural Networks ◽  
Continuous Variable ◽  
Model Parameters ◽  
Additional Parameter ◽  
Wide Range ◽  
Close Relationship ◽  
Rate Coding ◽  
One To One ◽  
The One

Cortical microcircuits exhibit complex recurrent architectures that possess dynamically rich properties. The neurons that make up these microcircuits communicate mainly via discrete spikes, and it is not clear how spikes give rise to dynamics that can be used to perform computationally challenging tasks. In contrast, continuous models of rate-coding neurons can be trained to perform complex tasks. Here, we present a simple framework to construct biologically realistic spiking recurrent neural networks (RNNs) capable of learning a wide range of tasks. Our framework involves training a continuous-variable rate RNN with important biophysical constraints and transferring the learned dynamics and constraints to a spiking RNN in a one-to-one manner. The proposed framework introduces only 1 additional parameter to establish the equivalence between rate and spiking RNN models. We also study other model parameters related to the rate and spiking networks to optimize the one-to-one mapping. By establishing a close relationship between rate and spiking models, we demonstrate that spiking RNNs could be constructed to achieve similar performance as their counterpart continuous rate networks.

Evidence of nonchiasmate bonds at metaphase I in inbred rye

1984 ◽  
Vol 26 (4) ◽  
pp. 409-414 ◽  
Author(s):  
M. C. Cermeño ◽  
J. Orellana ◽  
J. R. Lacadena
Keyword(s):  
Secale Cereale ◽  
Chiasma Frequency ◽  
Meiotic Pairing ◽  
Secale Cereale L ◽  
Chromosome 1R ◽  
Metaphase I

The loss of bound chromosome arms through early, middle, and late metaphase I has been analyzed in a plant of inbred rye (Secale cereale L.) heterozygous for a terminal heterochromatic C-band of the long arm of chromosome 1R. From the increase in the number of univalent pairs due to bound arm loss, and from the comparison between the frequencies of bound arms at metaphase I and recombinant chromosomes at anaphase I, it is concluded that some of the chromosome bonds appearing at metaphase I are actually nonchiasmate associations that can be considered as remnants of prophase pairing. Conclusions concerning recombination obtained solely from the analysis of chiasma frequency measured as bound arms may be invalid.Key words: inbred rye, C-heterochromatin, meiotic pairing, nonchiasmate bonds.

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