The quantitative analysis of chromosome pairing and chiasma formation based on the relative frequencies of MI configurations. V. Interchange trisomics

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.

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

Genome ◽

10.1139/g90-069 ◽

1990 ◽

Vol 33 (4) ◽

pp. 465-471 ◽

Cited By ~ 9

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.

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Analysis of chromosome pairing and breakage in pearl millet

Genetics Research ◽

10.1017/s0016672300019030 ◽

1982 ◽

Vol 40 (2) ◽

pp. 165-174 ◽

Cited By ~ 2

Author(s):

Prasad R. K. Koduru ◽

T. G. K. Murthy ◽

K. V. Lakshmi ◽

M. Krishna Rao

Keyword(s):

Quantitative Analysis ◽

Pearl Millet ◽

Chromosome Pairing ◽

Mutant Gene ◽

Pollen Grain ◽

Early Prophase ◽

Chromosome Fragmentation ◽

Reduced Frequency ◽

Synchronous Development ◽

The Relationship

SUMMARYThe relationship between chromosome pairing and chromosome fragmentation has been studied in a gene controlled mutant of pearl millet (2n = 14). Premeiotic mitosis, premeiotic cell development and early prophase I are normal without any fragments, which first appear at pachytene. The extent of fragmentation varies from zero to very extreme with two discrete classes of plants, namely those with partial fragmentation and those with multiple fragmentation. A quantitative analysis of bivalent distribution and the distribution of AI bridges in desynaptic and fragmented cells show all of them to be nonrandom events. We suggest that in cells showing partial fragmentation the bridges and fragments result from U-type exchanges at pachytene. The reduced frequency of AII bridges indicates relatively low sister chromatid reunion at pachytene. In multiple fragmented plants numerous minute fragments were seen from pachytene. Despite these anomalies most PMCs complete meiosis but subsequently abort at the pollen grain stage. The mutant gene also causes disturbances in the sequence of meiotic development in the ear and in the synchronous development of PMCs within an anther. It has no effect on the tapetum or on the physiological development of the anther.

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

Carlsberg Research Communications ◽

10.1007/bf02906519 ◽

1981 ◽

Vol 46 (5) ◽

pp. 305-346 ◽

Cited By ~ 55

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

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

Journal of Cell Science ◽

10.1242/jcs.12.1.143 ◽

1973 ◽

Vol 12 (1) ◽

pp. 143-161 ◽

Cited By ~ 1

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.

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