Preferential intragenomic chromosome pairing in two new diploid intergeneric hybrids between Hordeum and Secale

Genome ◽  
1987 ◽  
Vol 29 (4) ◽  
pp. 594-597 ◽  
Author(s):  
P. K. Gupta ◽  
George Fedak
Keyword(s):  
Key Words ◽  
Chromosome Pairing ◽  
Secale Cereale ◽  
Binomial Distribution ◽  
Homologous Chromosome ◽  
Intergeneric Hybrids ◽  
Hybrid Combination ◽  
Close Relationship ◽  
Chromosome Segments

Intergeneric hybrids involving Hordeum californicum with Secale anatolicum and Hordeum bogdanii with Secale cereale ssp. segetale were produced at a frequency of 1.3% of pollinated florets. Chiasmata frequencies of plants ranged from 0.13 to 0.21 per cell in the first hybrid combination and from 0.30 to 0.68 per cell in the second. The paucity of heteromorphic bivalents indicated absence of a close relationship between parental genomes. The associations in bivalents could be classified into Secale–Secale (R–R), Hordeum–Hordeum (H–H), and Secale–Hordeum (R–H) on the basis of difference in size of the chromosomes of Secale and Hordeum. Using a binomial distribution, it is shown that there was preferential intragenomic (R–R, H–H) chromosome pairing, which was attributed to the presence of homologous chromosome segments on nonhomologous chromosomes of the same genome. The distribution of Hordeum and Secale chromosomes to the poles at anaphase occurred at random. Key words: Hordeum, Secale, hybrids (intergeneric), chromosome pairing.

Nonhomologous Chromosome Pairing in Aegilops-Secale Hybrids

2015 ◽  
Vol 147 (4) ◽  
pp. 268-273 ◽  
Author(s):  
Yarui Su ◽  
Dale Zhang ◽  
Yuge Li ◽  
Suoping Li
Keyword(s):  
Chromosome Pairing ◽  
Secale Cereale ◽  
Embryo Rescue ◽  
Intergeneric Hybrids ◽  
Meiotic Pairing ◽  
Chromosome Homology ◽  
R And D ◽  
Young Embryo ◽  
Nonhomologous Chromosome

Intergeneric hybrids and amphidiploid hybrids from crosses of Aegilopstauschii and Secale cereale were produced using young embryo rescue. The hybrids showed complete sets of both parental chromosomes. The dihaploid plants showed an average meiotic pairing configuration of 10.84 I + 1.57 II + 0.01 III. Genomic in situ staining revealed 3 types of bivalent associations, i.e. D-D, R-R and D-R at frequencies of 8.6, 8.2 and 83.3%, respectively. Trivalents consisted of D-R-D or R-D-R associations. These results suggested that both intra- and intergenomic chromosome homology were contributed to chromosome pairing. Derived amphidiploids with 2n = 28 paired at metaphase I of meiosis as 4.51 I + 11.70 II + 0.03 III. Chromosome pairing of amphidiploids appeared more or less regular, i.e. bivalent-like with some trivalent configurations.

Intergeneric hybrids between Secale cereale (2x) and Thinopyrum intermedium (6x)

1986 ◽  
Vol 28 (3) ◽  
pp. 426-429 ◽  
Author(s):  
George Fedak ◽  
K. C. Armstrong
Keyword(s):  
Chromosome Pairing ◽  
Secale Cereale ◽  
Intergeneric Hybrids ◽  
Thinopyrum Intermedium ◽  
Paternal Parent ◽  
The Mean

Hybrids were obtained at the rate of 0.8% of pollinated florets in crossing of Thinopyrum intermedium spp. trichophorum onto Secale cereale cv. Puma. The morphology of the hybrid was similar to the paternal parent. The mean chromosome pairing in the hybrid was 18.80 I + 3.71 II + 0.56 III. A bivalent frequency of 0.04 was attributed to intergenomic pairing, the remainder being autosyndetic.Key words: hybrids (intergeneric), Secale, Thinopyrum, chromosome pairing, autosyndetic pairing.

Intergeneric hybrids between Hordeum jubatum and triticale (×Triticosecale Wittmack)

Genome ◽  
1987 ◽  
Vol 29 (4) ◽  
pp. 671-673 ◽  
Author(s):  
P. K. Gupta ◽  
G. Fedak
Keyword(s):  
Key Words ◽  
Chromosome Pairing ◽  
Intergeneric Hybrids ◽  
The Other ◽  
Wide Crosses ◽  
Isogenic Lines ◽  
Heterochromatic Block ◽  
Hordeum Jubatum ◽  
Triticosecale Wittmack

Hybrids of Hordeum jubatum (4x) were produced with two isogenic lines of 6x triticale (×Triticosecale Wittmack) cv. DRIRA, one carrying the normal heterochromatic block on the long arm of 7R (cv. DRIRA HH) and the other lacking 90% of it (cv. DRIRA EE). The two hybrids were produced at relative frequencies of 1.1 and 0.9% of pollinated florets, respectively. The chromosome pairing in both of these hybrids was negligible (chiasmata frequencies 0.11 and 0.15), indicating that heterochromatin on 7R had no effect on chromosome pairing in H. jubatum and that the expected autosyndetic pairing between two related genomes of H. jubatum was absent in this combination. Key words: wide crosses, intergeneric hybrids, triticale, Hordeum jubatum, chromosome pairing.

Non-homologous chromosome pairing during meiosis in haploid Brassica rapa

2021 ◽  
Author(s):  
Jiachen Yuan ◽  
Gongyao Shi ◽  
Yan Yang ◽  
Janeen Braynen ◽  
Xinjie Shi ◽  
...  
Keyword(s):  
Brassica Rapa ◽  
Chromosome Pairing ◽  
Homologous Chromosome ◽  
Homologous Chromosome Pairing

Intergeneric hybrids of Hordeum vulgare with Agropyron caninum and A. dasystachyum

1985 ◽  
Vol 27 (4) ◽  
pp. 387-392 ◽  
Author(s):  
George Fedak
Keyword(s):  
Hordeum Vulgare ◽  
Chromosome Pairing ◽  
Meiotic Chromosome ◽  
Intergeneric Hybrids ◽  
Spindle Fibre ◽  
Chromosome Behavior ◽  
Paternal Parent ◽  
Agropyron Caninum

Hybrids were obtained by pollinating Hordeum vulgare cv. Betzes with Agropyron caninum (4x) and A. dasystachyum (4x) at frequencies of 1.4 and 6.1% of pollinated florets, respectively. The hybrids were sterile and phenotypically resembled the paternal parent, except for floret structure which was intermediate between the parental types. Chromosome pairing at meiosis was very low and thus provided no indication of homoeology between parental genomes. Abnormal meiotic chromosome behavior in meiocytes that occurred in sectors on the 'Betzes' × A. dasystachyum hybrid was attributed to abnormal spindle fibre function.Key words: intergeneric hybrids, Hordeum vulgare, Agropyron caninum, Agropyron dasystachyum.

scholarly journals Regulating chromosomal movement by the cochaperone FKB-6 ensures timely pairing and synapsis

2017 ◽  
Vol 216 (2) ◽  
pp. 393-408 ◽  
Author(s):  
Benjamin Alleva ◽  
Nathan Balukoff ◽  
Amy Peiper ◽  
Sarit Smolikove
Keyword(s):  
Nuclear Envelope ◽  
Chromosome Pairing ◽  
Meiotic Prophase ◽  
Homologous Chromosome ◽  
Strand Break ◽  
Crossing Over ◽  
Chromosome Movement ◽  
Microtubule Network ◽  
Homologous Chromosome Pairing ◽  
Proper Movement

In meiotic prophase I, homologous chromosome pairing is promoted through chromosome movement mediated by nuclear envelope proteins, microtubules, and dynein. After proper homologue pairing has been established, the synaptonemal complex (SC) assembles along the paired homologues, stabilizing their interaction and allowing for crossing over to occur. Previous studies have shown that perturbing chromosome movement leads to pairing defects and SC polycomplex formation. We show that FKB-6 plays a role in SC assembly and is required for timely pairing and proper double-strand break repair kinetics. FKB-6 localizes outside the nucleus, and in its absence, the microtubule network is altered. FKB-6 is required for proper movement of dynein, increasing resting time between movements. Attenuating chromosomal movement in fkb-6 mutants partially restores the defects in synapsis, in agreement with FKB-6 acting by decreasing chromosomal movement. Therefore, we suggest that FKB-6 plays a role in regulating dynein movement by preventing excess chromosome movement, which is essential for proper SC assembly and homologous chromosome pairing.

Cytogenetics of Elymus caucasicus and Elymus longearistatus (Poaceae: Triticeae)

Genome ◽  
1991 ◽  
Vol 34 (6) ◽  
pp. 860-867 ◽  
Author(s):  
Kevin B. Jensen ◽  
Richard R.-C. Wang
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrid ◽  
Intergeneric Hybrids ◽  
Cytological Analysis ◽  
Meiotic Behavior ◽  
Pseudoroegneria Spicata ◽  
Central Asian ◽  
Elymus Lanceolatus

Two accessions of Elymus caucasicus (Koch) Tzvelev and three accessions of Elymus longearistatus (Boiss.) Tzvelev were studied to determine the meiotic behavior and chromosome pairing in the two taxa, their interspecific hybrid, and their hybrids with various "analyzer" parents. Interspecific and intergeneric hybrids of the target taxa were obtained with the following analyzer species: Pseudoroegneria spicata (Pursh) A. Löve (2n = 14, SS), Pseudoroegneria libanotica (Hackel) D. R. Dewey (2n = 14, SS), Hordeum violaceum Boiss. &Hohenacker (2n = 14, HH) (= Critesion violaceum (Boiss. &Hohenacker) A. Löve), Elymus lanceolatus (Scribn. &Smith) Gould (2n = 28, SSHH), Elymus abolinii (Drob.) Tzvelev (2n = 28, SSYY), Elymus pendulinus (Nevski) Tzvelev (2n = 28, SSYY), Elymus fedtschenkoi Tzvelev (2n = 28, SSYY), Elymus panormitanus (Parl.) Tzvelev (2n = 28, SSYY), and Elymus drobovii (Nevski) Tzvelev (2n = 42, SSHHYY). Cytological analysis of their F1 hybrids showed that E. caucasicus and E. longearistatus were allotetraploids comprising the same basic genomes. Chromosome pairing in the E. caucasicus × P. libanotica hybrid demonstrated that the target taxa contained the S genome, based on 6.1 bivalents per cell. The lack of chromosome pairing, less than one bivalent per cell, in the E. longearistatus × H. violaceum hybrid showed that the H genome was absent. Increased pairing in the tetraploid and pentaploid hybrids when the Y genome was introduced indicated that the second genome in the two taxa was a segmental homolog of the Y genome. The S and Y genomes in E. caucasicus and E. longearistatus have diverged from each other and from those in many of the eastern and central Asian SY tetraploids.Key words: genome, meiosis, chromosome pairing, morphology, hybrid, Triticeae.

A cohesin-based structural platform supporting homologous chromosome pairing in meiosis

2016 ◽  
Vol 62 (3) ◽  
pp. 499-502 ◽  
Author(s):  
Da-Qiao Ding ◽  
Tokuko Haraguchi ◽  
Yasushi Hiraoka
Keyword(s):  
Chromosome Pairing ◽  
Homologous Chromosome ◽  
Homologous Chromosome Pairing
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