scholarly journals Chromosome pairing, recombination nodules and chiasma formation in diploid Bombyx males

1980 ◽  
Vol 45 (6) ◽  
pp. 483-548 ◽  
Author(s):  
Preben Bach Holm ◽  
Søren Wilken Rasmussen
Keyword(s):  
Chromosome Pairing ◽  
Chiasma Formation ◽  
Recombination Nodules

scholarly journals Chromosome pairing, recombination nodules and chiasma formation in the basidiomycete coprinus cinereus

1981 ◽  
Vol 46 (5) ◽  
pp. 305-346 ◽  
Author(s):  
Preben B. Holm ◽  
Søren W. Rasmussen ◽  
Denise Zickler ◽  
Benjamin C. Lu ◽  
Jean Sage
Keyword(s):  
Chromosome Pairing ◽  
Chiasma Formation ◽  
Coprinus Cinereus ◽  
Recombination Nodules

Estimating meiotic chromosome pairing and recombination parameters in telocentric trisomics

Genome ◽  
2007 ◽  
Vol 50 (11) ◽  
pp. 1014-1028 ◽  
Author(s):  
J. Sybenga ◽  
H. Verhaar ◽  
D.G.A. Botje
Keyword(s):  
Gene Transfer ◽  
Chromosome Pairing ◽  
Genome Analysis ◽  
Meiotic Chromosome ◽  
Chiasma Formation ◽  
Chromosome Morphology ◽  
Test Material ◽  
Gene Localization ◽  
Maximum Information ◽  
Chromosome 1R

Telocentric trisomics (telotrisomics; one arm of a metacentric chromosome present in addition to two complete genomes) are used in theoretical studies of pairing affinities and chiasma formation in competitive situations and applied in genome analysis, gene localization, gene transfer, and breakage of close linkages. These applications require knowledge of the recombination characteristics of telotrisomics. Appropriate cytological and molecular markers and favorable chromosome morphology are not always available or applicable for quantitative analyses. We developed new mathematical models for extracting the maximum information from simple metaphase I observations. Two types of telotrisomics of the short arm of chromosome 1R of rye ( Secale cereale ), including several genotypes, were used as test material. In simple telotrisomics, pairing between morphologically identical complete chromosomes was more frequent than pairing between the telocentric and either of the normal chromosomes. In the telocentric substitution, morphologically identical telocentrics paired less frequently with each other than either one with the normal chromosome. Pairing partner switch was significant. Interaction between the two arms was variable. Variation within plants was considerable. Telotrisomics without markers are suitable for analyzing pairing preferences, for gene localization and gene transfer, and for breaking tight linkages, but less so for genome analysis.

scholarly journals Synaptonemal complex antigen location and conservation.

1987 ◽  
Vol 105 (1) ◽  
pp. 93-103 ◽  
Author(s):  
P B Moens ◽  
C Heyting ◽  
A J Dietrich ◽  
W van Raamsdonk ◽  
Q Chen
Keyword(s):  
Chromosome Pairing ◽  
Meiotic Prophase ◽  
Structural Integrity ◽  
Genetic Recombination ◽  
Positive Control ◽  
Western Blots ◽  
Lateral Element ◽  
Homologous Chromosomes ◽  
Recombination Nodules ◽  
Grain Distribution

The axial cores of chromosomes in the meiotic prophase nuclei of most sexually reproducing organisms play a pivotal role in the arrangement of chromatin, in the synapsis of homologous chromosomes, in the process of genetic recombination, and in the disjunction of chromosomes. We report an immunogold analysis of the axial cores and the synaptonemal complexes (SC) using two mouse monoclonal antibodies raised against isolated rat SCs. In Western blots of purified SCs, antibody II52F10 recognizes a 30- and a 33-kD peptide (Heyting, C., P. B. Moens, W. van Raamsdonk, A. J. J. Dietrich, A. C. G. Vink, and E. J. W. Redeker, 1987, Eur. J. Cell Biol., 43: 148-154). In spreads of rat spermatocyte nuclei it produces gold grains over the cores of autosomal and sex chromosomes. The cores label lightly during the chromosome pairing stage (zygotene) of early meiotic prophase and they become more intensely labeled when they are parallel aligned as the lateral elements of the SC during pachytene (55 grains/micron SC). Statistical analysis of electronically recorded gold grain positions shows that the two means of the bimodal gold grain distribution coincide with the centers of the lateral elements. At diplotene, when the cores separate, the antigen is still detected along the length of the core and the enlarged ends are heavily labeled. Shadow-cast SC preparations show that recombination nodules are not labeled. The continued presence suggests that the antigens serve a continuing function in the cores, such as chromatin binding, and/or structural integrity. Antibody III15B8, which does not recognize the 30- and 33-kD peptides, produces gold grains predominantly between the lateral elements. The grain distribution is bimodal with the mean of each peak just inside the pairing face of the lateral element. The antigen is present where and while the cores of the homologous chromosomes are paired. From the location and the timing, it is assumed that the antigen recognized by III15B8 functions in chromosome pairing at meiotic prophase. The two anti-rat SC antibodies label rat and mouse SCs but not rabbit or dog SCs. A positive control using human CREST (calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia) anti-centromere serum gives equivalent labeling of SC centromeres in the rat, mouse, rabbit, and dog. It is concluded that the SC antigens recognized by II52F10 and III15B8 are not widely conserved. The two antibodies do not bind to cellular or nuclear components of somatic cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Analysis of synaptonemal complexes and chromosome pairing at metaphase I in the diploid intergeneric hybrid Lolium multiflorum × Festuca drymeja

Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 465-471 ◽  
Author(s):  
Hum M. Thomas ◽  
W. G. Morgan
Keyword(s):  
Chromosome Pairing ◽  
Complex Analysis ◽  
Lolium Multiflorum ◽  
Intergeneric Hybrid ◽  
Chiasma Formation ◽  
Genotypic Effect ◽  
Synaptonemal Complexes ◽  
Dna Values ◽  
Synaptonemal Complex Analysis ◽  
Metaphase I

The synaptonemal complexes in the diploid hybrid Lolium multiflorum × Festuca drymeja were examined by the surface spreading technique, and chromosome pairing at metaphase I was analysed. Synaptonemal complex analysis revealed "illegitimate" pairing, including multivalents and foldback pairing. At metaphase I, most chiasmata were between chromosomes of the same genome, and again multivalents were found. It was concluded that most synaptonemal complexes resulted in chiasma formation. The effects of the large differences in DNA values of the two species and the possible genotypic effect of F. drymeja on chromosome pairing are discussed.Key words: Lolium-Festuca, synaptonemal complexes, nonhomologous pairing, DNA values.

The Effect of Spindle Inhibitors Applied before Meiosis on Meiotic Chromosome Pairing

1973 ◽  
Vol 12 (1) ◽  
pp. 143-161 ◽  
Author(s):  
G. A. DOVER ◽  
R. RILEY
Keyword(s):  
Chromosome Pairing ◽  
Chloral Hydrate ◽  
Control Mechanism ◽  
Meiotic Chromosome ◽  
Chiasma Formation ◽  
Meiotic Pairing ◽  
Mitotic Spindles ◽  
Pollen Mother Cells ◽  
Meiotic Chromosome Pairing ◽  
Mother Cells

Injection of 0.5% colchicine into immature tillers of genotypes of Triticum aestivum, T. aestivum x Aegilops mutica and T. aestivum x Secale cereale hybrids induces asynapsis at first meiotic metaphase irrespective of the homologous or homoeologous nature of the potential pairing chromosomes. The induction of asynapsis occurs at a time during and immediately following the last premeiotic mitosis of pollen mother cells. No disruption of synapsis and chiasma formation occurs in anthers having pollen mother cells originally at leptotene or immediately prior to leptotene when cultured in White's medium plus colchicine. Tetraploid and octaploid pollen mother cells resulting from the disruption of premeiotic spindles by colchicine show pairing of chromosomes only in bivalents, in genotypes normally having a degree of multivalent pairing configurations. The induction of multipolar mitotic spindles with 0.01% colchicine results in the development of pollen mother cell mosaics with different numbers of chromosomes. Such cells show high levels of chromosome pairing, including multivalents, in some genotypes that normally have very little chromosome pairing. The injection of 0.5% chloral hydrate during the last premeiotic mitosis of the archesporium causes no disturbances of meiotic pairing. The results are discussed with reference to the hypothesis that the control mechanism of meiotic chromosome pairing involves centromeric microtubules of the spindle (not affected by chloral hydrate) that are responsible for the positional adjustment, during the last mitotic anaphase, of potential pairing partners.

HEAT INDUCED TETRAPLOIDY IN BARLEY

1936 ◽  
Vol 14c (12) ◽  
pp. 445-447 ◽  
Author(s):  
F. H. Peto
Keyword(s):  
Chromosome Pairing ◽  
Chiasma Formation

A tetraploid sector on a barley spike was induced by germinating and growing barley for seven days at 35 °C. Tetraploid and diploid florets from the same spike were compared with respect to chromosome pairing and chiasma formation.

Comparative analysis of female and male meiosis in three meiotic mutants of tomato

Genome ◽  
1997 ◽  
Vol 40 (6) ◽  
pp. 879-886 ◽  
Author(s):  
Francis W. J. Havekes ◽  
J. Hans de Jong ◽  
Christa Heyting
Keyword(s):  
Comparative Analysis ◽  
Chromosome Pairing ◽  
Meiotic Prophase ◽  
Chiasma Frequency ◽  
Chiasma Formation ◽  
Male Meiosis ◽  
Wild Type ◽  
Female Meiosis ◽  
Similar Reduction ◽  
Meiotic Mutants

Female meiosis was analysed in squash preparations of ovules from three meiotic mutants and wild-type plants of tomato. In the completely asynaptic mutant as6, chromosome pairing and chiasma formation were virtually absent in both sexes. In the partially asynaptic mutant asb, with intermediate levels of chromosome pairing at pachytene, there were a higher number of chiasmate chromosome arms in female meiosis than in male meiosis, whereas in the desynaptic mutant as5 there were normal levels of chromosome pairing at pachytene and a similar reduction in chiasma frequency in the two sexes. In wild-type tomato, we found slightly higher numbers of chiasmate chromosome arms in female meiosis than in male meiosis. We propose that the higher female chiasma frequencies in mutant asb and wild-type tomato result from a longer duration of female meiotic prophase. This would allow chromosomes more time to pair and recombine. It is possible that a longer duration of prophase I does not affect mutants as5 and as6, either because the meiotic defect acts before the pairing process begins (in as6) or because it acts at a later stage and involves chiasma maintenance (in as5).Key words: female meiosis, tomato, chiasma, mutant.

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