scholarly journals Direct evidence for crossover and chromatid interference in meiosis of two plant hybrids (Lolium multiflorum×Festuca pratensis and Allium cepa×A. roylei)

2020 ◽  
Author(s):  
Marco Tulio Mendes Ferreira ◽  
Marek Glombik ◽  
Kateřina Perničková ◽  
Martin Duchoslav ◽  
Olga Scholten ◽  
...  
Keyword(s):  
Allium Cepa ◽  
Direct Evidence ◽  
Lolium Multiflorum ◽  
Crossing Over ◽  
Festuca Pratensis ◽  
Physical Measure ◽  
Crossover Interference ◽  
Chromosome Arm ◽  
Double Crossovers

Abstract Crossing over, in addition to its strictly genetic role, also performs a critical mechanical function, by bonding homologues in meiosis. Hence, it is responsible for an orderly reduction of the chromosome number. As such, it is strictly controlled in frequency and distribution. The well-known crossover control is positive crossover interference which reduces the probability of a crossover in the vicinity of an already formed crossover. A poorly studied aspect of the control is chromatid interference. Such analyses are possible in very few organisms as they require observation of all four products of a single meiosis. Here, we provide direct evidence of chromatid interference. Using in situ probing in two interspecific plant hybrids (Lolium multiflorum×Festuca pratensis and Allium cepa×A. roylei) during anaphase I, we demonstrate that the involvement of four chromatids in double crossovers is significantly more frequent than expected (64% versus 25%). We also provide a physical measure of the crossover interference distance, covering ~30–40% of the relative chromosome arm length, and show that the centromere acts as a barrier for crossover interference. The two arms of a chromosome appear to act as independent units in the process of crossing over. Chromatid interference has to be seriously addressed in genetic mapping approaches and further studies.

The pattern of homoeologous recombination in triploid hybrids of Lolium multiflorum with Festuca pratensis

Genome ◽  
1999 ◽  
Vol 42 (4) ◽  
pp. 720-726 ◽  
Author(s):  
Z Zwierzykowski ◽  
A J Lukaszewski ◽  
B Naganowska ◽  
A Lesniewska
Keyword(s):  
Parental Species ◽  
Lolium Multiflorum ◽  
Festuca Pratensis ◽  
Meiotic Pairing ◽  
Homoeologous Recombination ◽  
Translocation Breakpoints ◽  
Zygotic Selection ◽  
Homoeologous Chromosomes ◽  
Pairing Initiation

Homoeologous chromosomes of Lolium-Festuca hybrids are capable of frequent meiotic pairing and recombination. The frequency and distribution of recombination was studied by genomic in situ hybridization in backcross progenies of reciprocal triploid hybrids of Lolium multiflorum with Festuca pratensis. Significant differences in the male transmission of the parental and translocated chromosomes were observed depending on the cytoplasm of the F1 hybrids and the ploidy level of the female test cross partner. The frequency of intergeneric translocations in the progeny indicated that, on average, there must have been at least 4.5 homoeologous arms paired in the F1 hybrids; the actual frequency might have been higher because of pre- or post-zygotic selection against the F. pratensis chromatin, which probably eliminated certain gametes with Festuca-Lolium translocations. Both parental species are known for localized distal chiasmata, but the intergeneric translocation breakpoints were distributed along the entire lengths of the chromosome arms. The change in the distribution of homoeologous recombination might have been related to different pairing initiation of homologues and homoeologues. It probably resulted from allocation of additional chiasmata to chromosome arms and produced a net increase in recombination.Key words: homoeologous exchanges, Lolium-Festuca, translocations, recombination.

The Budding Yeast Msh4 Protein Functions in Chromosome Synapsis and the Regulation of Crossover Distribution

Genetics ◽  
2001 ◽  
Vol 158 (3) ◽  
pp. 1013-1025 ◽  
Author(s):  
Janet E Novak ◽  
Petra B Ross-Macdonald ◽  
G Shirleen Roeder
Keyword(s):  
Mismatch Repair ◽  
Budding Yeast ◽  
Null Mutation ◽  
Crossing Over ◽  
Wild Type ◽  
Crossover Interference ◽  
Meiotic Chromosomes ◽  
Chromosome Synapsis ◽  
Protein Functions ◽  
Or Gene

AbstractThe budding yeast MSH4 gene encodes a MutS homolog produced specifically in meiotic cells. Msh4 is not required for meiotic mismatch repair or gene conversion, but it is required for wild-type levels of crossing over. Here, we show that a msh4 null mutation substantially decreases crossover interference. With respect to the defect in interference and the level of crossing over, msh4 is similar to the zip1 mutant, which lacks a structural component of the synaptonemal complex (SC). Furthermore, epistasis tests indicate that msh4 and zip1 affect the same subset of meiotic crossovers. In the msh4 mutant, SC formation is delayed compared to wild type, and full synapsis is achieved in only about half of all nuclei. The simultaneous defects in synapsis and interference observed in msh4 (and also zip1 and ndj1/tam1) suggest a role for the SC in mediating interference. The Msh4 protein localizes to discrete foci on meiotic chromosomes and colocalizes with Zip2, a protein involved in the initiation of chromosome synapsis. Both Zip2 and Zip1 are required for the normal localization of Msh4 to chromosomes, raising the possibility that the zip1 and zip2 defects in crossing over are indirect, resulting from the failure to localize Msh4 properly.

scholarly journals Crossover Interference in Arabidopsis

Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1631-1639 ◽  
Author(s):  
G P Copenhaver ◽  
E A Housworth ◽  
F W Stahl
Keyword(s):  
Arabidopsis Thaliana ◽  
Degrees Of Freedom ◽  
Double Strand Breaks ◽  
Crossing Over ◽  
Chi Square ◽  
Strand Breaks ◽  
Crossover Interference

AbstractThe crossover distribution in meiotic tetrads of Arabidopsis thaliana differs from those previously described for Drosophila and Neurospora. Whereas a chi-square distribution with an even number of degrees of freedom provides a good fit for the latter organisms, the fit for Arabidopsis was substantially improved by assuming an additional set of crossovers sprinkled, at random, among those distributed as per chi square. This result is compatible with the view that Arabidopsis has two pathways for meiotic crossing over, only one of which is subject to interference. The results further suggest that Arabidopsis meiosis has >10 times as many double-strand breaks as crossovers.

A Demonstration of a 1:1 Correspondence Between Chiasma Frequency and Recombination Using a Lolium perenne/Festuca pratensis Substitution

Genetics ◽  
2002 ◽  
Vol 161 (1) ◽  
pp. 307-314 ◽  
Author(s):  
J King ◽  
L A Roberts ◽  
M J Kearsey ◽  
H M Thomas ◽  
R N Jones ◽  
...  
Keyword(s):  
Lolium Perenne ◽  
Chiasma Frequency ◽  
Chiasma Formation ◽  
Grass Species ◽  
Festuca Pratensis ◽  
Single Chromosome ◽  
Length Polymorphisms ◽  
Amplified Fragment Length Polymorphisms ◽  
Frequency Counts

Abstract A single chromosome of the grass species Festuca pratensis has been introgressed into Lolium perenne to produce a diploid monosomic substitution line (2n = 2x = 14). The chromatin of F. pratensis and L. perenne can be distinguished by genomic in situ hybridization (GISH), and it is therefore possible to visualize the substituted F. pratensis chromosome in the L. perenne background and to study chiasma formation in a single marked bivalent. Recombination occurs freely in the F. pratensis/L. perenne bivalent, and chiasma frequency counts give a predicted map length for this bivalent of 76 cM. The substituted F. pratensis chromosome was also mapped with 104 EcoRI/Tru91 and HindIII/Tru91 amplified fragment length polymorphisms (AFLPs), generating a marker map of 81 cM. This map length is almost identical to the map length of 76 cM predicted from the chiasma frequency data. The work demonstrates a 1:1 correspondence between chiasma frequency and recombination and, in addition, the absence of chromatid interference across the Festuca and Lolium centromeres.

Inflorescence development and seed production in Lolium spp. × Festuca pratensis tetraploid hybrids

1975 ◽  
Vol 85 (2) ◽  
pp. 301-307 ◽  
Author(s):  
P. Cremades ◽  
E. W. Bean
Keyword(s):  
Seed Production ◽  
Lolium Perenne ◽  
Lolium Multiflorum ◽  
Pollen Viability ◽  
Festuca Pratensis ◽  
Inflorescence Development ◽  
Tetraploid Hybrid ◽  
Pollen Release ◽  
Sufficient Variation ◽  
Reproductive Characters

SUMMARYThe reproductive development and seed production characters of a Lolium multiflorum × Festuca pratensis tetraploid hybrid and a Lolium perenne × Festuca pratensis tetraploid hybrid were compared with those of their tetraploid parental cultivars. Experiments were carried out under glasshouse and natural conditions; single plants were studied as only small quantities of seed were available from the breeder. The lowtemperature/short-day requirements for inflorescence induction of the two hybrids were in between those of the corresponding parental species. The variance of the date at which vegetative primordia changed to the reproductive condition was greater in the hybrids than in the parental cultivars, but the variance of the dates of inflorescence emergence were similar for the hybrids and parental cultivars. Inflorescences ranged from the Lolium type with only sessile spikelets to the Festuca type with primary branches. Inner glumes, which are absent in the Lolium parents but present in Festuca pratensis, were found in the hybrids, though not in all spikelets. In the Lolium perenne × Festuca pratensis hybrid pollen release, potential pollen viability and floret fertility were low, but the Lolium multiflorum × Festuca pratensis hybrid produced large amounts of pollen with a higher potential viability and had floret fertilities similar to those of its two parental cultivars. There was sufficient variation in reproductive characters for further selection, particularly in the Lolium perenne × Festuca pratensis hybrid.

Green rust as a precursor for magnetite: an in situ synchrotron based study

2008 ◽  
Vol 72 (1) ◽  
pp. 201-204 ◽  
Author(s):  
A. Sumoondur ◽  
S. Shaw ◽  
I. Ahmed ◽  
L. G. Benning
Keyword(s):  
Direct Evidence ◽  
Green Rust ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Subsequent Transformation ◽  
Rapid Formation ◽  
Reaction Proceeds

AbstractIn this study, direct evidence for the formation of magnetite via a green rust intermediate is reported. The Fe(II) induced transformation of ferrihydrite, was quantified in situ and under O2-free conditions using synchrotron-based time-resolved energy dispersive X-ray diffraction. At pH 9 and Fe(II)/Fe(III) ratios of 0.5 and 1, rapid growth (6 min) of sulphate green rust and its subsequent transformation to magnetite was observed. Electron microscopy confirmed these results, showing the initial rapid formation of hexagonal sulphate green rust particles, followed by the corrosion of the green rust as magnetite growth occurred, indicating that the reaction proceeds via a dissolution-reprecipitation mechanism. At pH 7 and Fe(II)/Fe(III) ratio of 0.5, sulphate green rust was the stable phase, with no transformation to magnetite.

scholarly journals Comparison of agronomic characters of Festulolium, Festuca pratensis Huds. and Lolium multiflorum Lam. genotypes under high elevation conditions in Turkey

1970 ◽  
Vol 37 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Ilknur Akgun ◽  
Metin Tosun ◽  
Suleyman Sengul
Keyword(s):  
Seed Yield ◽  
Crude Protein ◽  
Dry Matter ◽  
Lolium Multiflorum ◽  
High Elevation ◽  
Ash Content ◽  
Festuca Pratensis ◽  
Higher Plant ◽  
Green Matter ◽  
Significant Difference

Prior {Lolium perenne × Festuca pratensis) and Elmet (Lolium multiflorum × Festuca pratensis) cultivars were compared with Festuca pratensis Huds. and Lolium multiflorum Lam. genotypes for some agronomical characteristics (green and dry matter yields, crude protein, seed yield, crude ash content) under Erzurum ecological conditions. Analysis of variance and mean separation were performed using the SPSS 11.0 computer program. There was a significant difference among genotypes in every character tested except for green and dry matter yield and crude ash content. Hybrid genotypes had higher plant height, dry and green matter yield, seed yield per plant and crude protein yield except 1000-seed weight. Elmet performed better than Prior except for seed yield per plant.   Key words: Festulolium, Lolium, Festuca, Yield, Crude protein, Crude ash doi:10.3329/bjb.v37i1.1556 Bangladesh J. Bot. 37(1): 1-6, 2008 (June)

scholarly journals Application of SCoT markers for accessing of genetic diversity of gramineous forage grass species

2021 ◽  
Vol 901 (1) ◽  
pp. 012038
Author(s):  
Yu M Mavlyutov ◽  
A O Shamustakimova ◽  
I A Klimenko
Keyword(s):  
Lolium Multiflorum ◽  
Molecular Genetic ◽  
Grass Species ◽  
Festuca Rubra ◽  
Festuca Pratensis ◽  
Forage Grass ◽  
Marker System ◽  
Scot Marker ◽  
Dna Profiles ◽  
Subsequent Identification

Abstract Using the SCoT marker system, 8 varieties of cereal grasses belonging to 5 species were analyzed: Festuca pratensis, Lolium perenne, Lolium multiflorum, Festuca rubra, Festulolium. Of the 10 tested SCoT markers, 7 informative markers were selected that reveal interspecies genetic polymorphism. According to the results of the analysis, DNA profiles characteristic of each studied species were obtained, and primers allowing to detect intervarietal differences for subsequent identification and molecular genetic passportization were selected.

Initial Stages of InAs Quantum Dots Evolution in GaAs/AlAs Matrixes

2002 ◽  
Vol 749 ◽  
Author(s):  
Michael Yakimov ◽  
Vadim Tokranov ◽  
Alex Katnelson ◽  
Serge Oktyabrsky
Keyword(s):  
Quantum Dots ◽  
Direct Evidence ◽  
Matrix Material ◽  
Single Layer ◽  
High Energy ◽  
Inas Quantum Dots ◽  
Auger Signal ◽  
The Matrix ◽  
Growth Evolution

ABSTRACTWe have studied the first phases of post-growth evolution of InAs quantum dots (QDs) using in-situ Auger electron spectroscopy in conjunction with Reflection High Energy Electron Diffraction (RHEED). Direct evidence for InAs intermixing with about 6ML (monolayers) of the matrix material is found from Auger signal behavior during MBE overgrowth of InAs nanostructures. Re-establishment of 2D growth mode by overgrowth with GaAs or AlAs was monitored in single-layer and multi-layer QD structures using RHEED. Decay process of InAs QDs on the surface is found to have activation energy of about 1.1 eV that corresponds to In intermixing with the matrix rather than evaporation from the surface.

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