Relation between loss of chromosome associations at metaphase I and interference estimates in rye

Genome ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 19-24
Author(s):  
A. Roca ◽  
T. Naranjo ◽  
P. G. Goicoechea ◽  
R. Giraldez
Keyword(s):  
Secale Cereale ◽  
Translocation Breakpoint ◽  
Negative Interference ◽  
Secale Cereale L ◽  
Chromosome Associations ◽  
I Cells ◽  
Chiasma Interference ◽  
Metaphase I

Interference between metaphase I associations (bonds) in specific segments of the chromosomes involved in translocation T242W of rye has been studied. Different values of coincidence were obtained at mid- and late metaphase I for all segment pairs analyzed. At mid-metaphase I there is negative interference between segments opposite to the translocation breakpoint and there is no cross-centromere interference. At late metaphase I there is negative interference in all these segment pairs. The comparison between mid- and late metaphase I cells also indicated that the frequency with which some of these segments are associated decreases along this stage. The possible causes of this decrease and its relation to the differences in coincidence estimates are discussed.Key words: Secale cereale L., translocations, chiasma interference.

Interstitial chiasmata and centromere orientation in heterozygotes for a translocation in rye

Genome ◽  
1987 ◽  
Vol 29 (4) ◽  
pp. 647-657 ◽  
Author(s):  
P. G. Goicoechea ◽  
A. Roca ◽  
T. Naranjo ◽  
R. Giraldez
Keyword(s):  
Key Words ◽  
Secale Cereale ◽  
Chiasma Frequency ◽  
Recombination Fraction ◽  
Translocation Breakpoint ◽  
Meiotic Behaviour ◽  
Significant Excess ◽  
Alternate Orientation ◽  
Chiasma Interference ◽  
Metaphase I

The meiotic behaviour of plants heterozygous for translocation T242W of rye (involving 2RL and 6RL) and an interstitial C-band in 2RL has been analyzed. Chain and frying pan quadrivalents predominate. The following results have further been obtained: (i) double chiasmata occur in the interstitial segment carrying the C-band; (ii) from the frequency of being bound at metaphase I and the frequency of recombinant chromosomes at anaphase I, estimates of chiasma frequencies (and chiasma interference) in interstitial segments have been derived; (iii) estimates of the recombination fraction between the interstitial C-band and the translocation breakpoint have been obtained from offspring analysis; (iv) there is a difference in the frequency of alternate orientation between configurations with and without interstitial chiasmata (adjacent-2 has not been observed and a small but significant excess of alternate vs. adjacent-1 coorientation appears). Without intersitial chiasmata, alternate orientation predominates. The possible reasons for these differences are discussed. Key words: Secale cereale, translocations, chiasma frequency, centromere orientation.

Comparison between synaptonemal complexes at pachytene and chromosome association at metaphase I in heterozygotes for a "nonreciprocal" translocation of rye

Genome ◽  
1989 ◽  
Vol 32 (6) ◽  
pp. 983-991 ◽  
Author(s):  
T. Naranjo ◽  
A. Roca ◽  
P. G. Goicoechea ◽  
J. H. de Jong ◽  
W. D. Smilde
Keyword(s):  
Complex Formation ◽  
Synaptonemal Complex ◽  
Secale Cereale ◽  
Chiasma Formation ◽  
Chromosome Association ◽  
Simultaneous Occurrence ◽  
Negative Interference ◽  
Secale Cereale L ◽  
Synaptonemal Complex Formation ◽  
Metaphase I

A comparative analysis of synaptonemal complex formation at pachytene and chromosome association at metaphase I was carried out in heterozygotes for translocation T242W (2R/6R) of rye (Secale cereale L.). Synaptonemal complex formation supported earlier light microscopic observations that one exchanged segment of this translocation was very small and restricted to the telomere or had been lost. Negative interference between the interstitial segments with respect to chiasma formation was detected at metaphase I. This interference was apparently the result of the simultaneous occurrence of either asynapsis or nonhomologous pairing around the translocation point at pachytene. Negative interference detected across the centromere of 6R was attributed to nonhomologous pairing. The presence of an intercalary C-band in the interstitial segment 2RLi or in the 1RS arm had no apparent influence on synaptonemal complex formation. Unmatched ends of synaptonemal complex 1R and of the multivalent were in most cases associated with heterozygosity for the telomeric C-heterochromatin.Key words: Secale cereale, translocation, synapsis, interference, C-banding.

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.

scholarly journals ASSOCIATION OF ISOZYMES WITH A RECIPROCAL TRANSLOCATION IN CULTIVATED RYE (SECALE CEREALE L.)

Genetics ◽  
1985 ◽  
Vol 109 (1) ◽  
pp. 177-193
Author(s):  
Ana M Figueiras ◽  
Maria T Gonzalez-Jaen ◽  
Julio Salinas ◽  
Cesar Benito
Keyword(s):  
Secale Cereale ◽  
Reciprocal Translocation ◽  
Chromosome Arrangement ◽  
Electrophoretic Patterns ◽  
Meiotic Configuration ◽  
Chromosome Arm ◽  
Secale Cereale L ◽  
Metaphase I

ABSTRACT In rye (Secale cereale L. cv. "Ailés") the progeny of a cross between a structural heterozygote for a reciprocal translocation (involving the 1R chromosome) and a homozygote for the standard chromosome arrangement were analyzed for the electrophoretic patterns of eight different leaf isozymes and also for their meiotic configuration at metaphase I.—The Got-3 and Mdh-2b loci are linked to each other and also to the reciprocal translocation. The Mdh-2b locus is located in the interstitial segment of the 3Rq chromosome arm, with an estimated distance of 8 cM to the breakpoint. Therefore, the reciprocal translocation involves the 1R and 3R chromosomes.—Also, the Mdh-1 and 6-Pgd-2 loci are linked (16 ± 3 cM) and have been located on the 2Rq arm. Finally, the Per-3 and Per-4 loci are located on the 2Rp chromosome arm at an estimated distance of 26 ± 4 cM.

Meiotic chromosome association in diploid and tetraploid Avena strigosa Schrel.

Genome ◽  
1989 ◽  
Vol 32 (6) ◽  
pp. 972-977 ◽  
Author(s):  
S. N. Zadoo ◽  
R. N. Choubey ◽  
S. K. Gupta ◽  
J. Sybenga
Keyword(s):  
High Frequency ◽  
Meiotic Chromosome ◽  
Chromosome Association ◽  
Present Material ◽  
Negative Interference ◽  
Avena Strigosa ◽  
Partner Exchange ◽  
Quadrivalent Frequency ◽  
Chiasma Interference ◽  
Metaphase I

In diploid Avena strigosa the frequency and distribution of open (rod) bivalents suggest that a limited number of chromosomes, possibly two, fail to have a chiasma in one (short) arm in over 60% of the cells. In the tetraploid these are expected to form bivalents instead of quadrivalents at metaphase I of meiosis in a high frequency. In addition, interstitial chiasmata are expected in the long arms of these chromosomes, when involved in quadrivalents. In the tetraploid the frequency of quadrivalents is indeed low, and the configurations with interstitial chiasmata are distributed as expected. However, application of Sybenga's models suggests that the pairing system rather than the chiasma system would be responsible for the low quadrivalent frequency. It is suggested that apparent negative chiasma interference across the point of pairing partner exchange, resulting from variation in its location, invalidates application of these models to the present material. Negative interference results in an even higher than expected open bivalent frequency, in combination with a relatively high ring quadrivalent frequency. In addition, not only the subacrocentric chromosomes but also the more metacentric chromsomes, by this same mechanism, tend to form open bivalents more often than in the diploid.Key words: meiosis, bivalent, quadrivalent, diploid, tetraploid, Avena strigosa

Synapsis and chiasma formation in a ditelo-substituted haploid of rye

Genome ◽  
1991 ◽  
Vol 34 (1) ◽  
pp. 109-120 ◽  
Author(s):  
J. H. de Jong ◽  
F. Havekes ◽  
A. Roca ◽  
T. Naranjo
Keyword(s):  
Synaptonemal Complex ◽  
Secale Cereale ◽  
Chiasma Formation ◽  
Chromosome Length ◽  
C Banding ◽  
Chromosome Associations ◽  
Synaptonemal Complex Formation ◽  
Chromosome 1R ◽  
In Cells ◽  
Metaphase I

Synapsis and chiasma formation were analyzed in a ditelo-substituted haploid of rye (Secale cereale), in which chromosome 1R was replaced by its telosomes. The study was made by comparing synaptonemal complex formation at early meiotic prophase I, chromosome associations at metaphase I, and recombinant chromosomes at anaphase I and prophase II. For the analysis of synaptonemal complexes, 41 nuclei at stages ranging from leptotene to early diplotene were selected. In the leptotene and early zygotene nuclei, numerous alignments of axial cores involving the same or different chromosomes were observed. Pairing initiation sites occurred at both interstitial and distal segments. Throughout zygotene the extent of pairing gradually increases, with values up to 84.8% at a stage that is morphologically comparable with late pachytene. Pairing-partner exchanges were frequently observed in zygotene nuclei, giving rise to multiple associations encompassing all or most of the chromosomes. In cells at metaphase I multivalents were very rare (2%), indicating elimination of most pairing-partner exchanges. In cells at metaphase I, anaphase I, and prophase II chromosome length, centromere position, and C-banding pattern enable the identification of the chromosomes 1RS, 1RL, 4R, 5R, and 6R, and the distinction of three metacentric chromosomes (RM1, RM2, and RM3). Metaphase I bonds were found to be nonrandomly distributed. Associations between the arms 4RL, 5RL, 6RL, and RM1L, all of them without telomeric C-bands, were more frequent than between the remaining arms. The bonds were mainly located at the distal parts of the chromosomes. The frequency of recombinant chromosomes at anaphase I or prophase II suggests that metaphase I bonds were true chiasmata.Key words: Secale cereale, haploid, synaptonemal complex, chiasmate bonds, C-banding.

Effet antioxydant et antihyperglycémiant du seigle (Secale cereale L.) et du sorgho (Sorghum bicolor L.) chez le rat Wistar rendu diabétique

2018 ◽  
Vol 16 (S1) ◽  
pp. S273-S283
Author(s):  
Z. Mami-Soualem ◽  
N. Brixi ◽  
C. Beghdad ◽  
M. Belarbi
Keyword(s):  
Sorghum Bicolor ◽  
Secale Cereale ◽  
Stress Oxydant ◽  
Habitudes Alimentaires ◽  
Diabète Sucré ◽  
Secale Cereale L ◽  
Vitamine C ◽  
Fibres Alimentaires ◽  
Peroxydation Lipidique ◽  
Sorghum Bicolor L

Le changement des habitudes alimentaires au cours de ces dernières années a abouti à l’apparition des maladies dites de civilisation, parmi elles le diabète sucré. Des approches diétothérapeutiques privilégient la consommation des produits céréaliers sous la forme la plus complète possible. Ce travail a pour but de tester l’efficacité des régimes expérimentaux préparés à base des grains complets des deux céréales, le sorgho (Sorghum bicolor L.) et le seigle (Secale cereale L.), sur la correction de l’hyperglycémie et des marqueurs du stress oxydant associés au diabète chez le rat mâle Wistar. Les résultats montrent que les rats diabétiques, soumis au régime seigle pendant quatre semaines, présentent une diminution significative de la glycémie qui atteint les 53,95 % à la fin de l’expérimentation, ce qui fait que leur taux en glycémie se rapproche de celui des normoglycémiques. Le sorgho blanc présente, d’une part, une diminution significative de la peroxydation lipidique intracellulaire et, d’autre part, une augmentation de l’activité de la glutathion peroxydase, la glutathion réductase ainsi que la vitamine C. Ces approches méthodologiques peuvent, en améliorant la connaissance de l’importance des céréales (fibres alimentaires solubles et des polyphénols) dans l’évolution du diabète, aboutir à des recommandations et à une éducation nutritionnelle du diabétique.

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