Interspecific hybrids between a transgenic rapeseed (Brassica napus) and related species: cytogenetical characterization and detection of the transgene

Genome ◽  
1993 ◽  
Vol 36 (6) ◽  
pp. 1099-1106 ◽  
Author(s):  
M. C. Kerlan ◽  
A. M. Chevre ◽  
F. Eber
Keyword(s):  
Chromosome Pairing ◽  
Related Species ◽  
Interspecific Hybrids ◽  
Plant Production ◽  
Triploid Hybrid ◽  
Bar Gene ◽  
Meiotic Behavior ◽  
Gene Dispersal ◽  
Gene Characterization ◽  
Transgenic Rapeseed

In interspecific hybrids produced between a transgenic rapeseed, an allotetraploid species, resistant to herbicide, phosphinotricin, and five diploid related species, the risk for gene introgression in weed genomes was explored through cytogenetic and bar gene characterizations. Among the 75 hybrids studied, most had the expected triploid structure, with the exception of B. napus – B. oleracea amphidiploid plants and one B. napus – S. arvensis amphidiploid plant. In triploid hybrid plants, the reciprocal hybrids did not exhibit any difference in their meiotic behavior. The comparison of the percentage of chromosome pairing in the hybrids with that of haploid rapeseed permit to conclude that allosyndesis between AC genomes and related species genomes took place. This possibility of recombination was confirmed by the presence of multivalent associations in all the interspecific hybrids. Nevertheless, in B. napus – B. adpressa hybrids a control of chromosome pairing seemed to exist. The possibility of amphidiploid plant production directly obtained in the F1 generation increased the risk of gene dispersal. The B. napus – B. oleracea amphidiploid plant presented a meiotic behavior more regular than that of the B. napus – S. arvensis amphidiploid plant. Concerning the herbicide bar gene characterization, the presence of the gene detected by DNA amplification was correlated with herbicide resistance, except for two plants. Different hypotheses were proposed to explain these results. A classification of the diploid species was established regarding their gene dispersal risk based on the rate of allosyndesis between chromosomes of AC genomes of rapeseed and the genomes of the related species.Key words: Brassicaceae, transgenic rapeseed, risk assessment, interspecific hybrids, chromosome pairing, bar gene characterization.

CHROMOSOME PAIRING IN TWO INTERSPECIFIC HYBRIDS OF TRIFOLIUM

1970 ◽  
Vol 12 (4) ◽  
pp. 790-794 ◽  
Author(s):  
Chi-Chang Chen ◽  
Pryce B. Gibson
Keyword(s):  
Phylogenetic Relationship ◽  
Chromosome Pairing ◽  
Trifolium Repens ◽  
Interspecific Hybrids ◽  
Triploid Hybrid ◽  
Close Phylogenetic Relationship ◽  
Metaphase I

Both Trifolium repens (2n = 32) and T. nigrescens (2n = 16) formed bivalents during meiosis. However, their triploid hybrid showed an average of 4.27 trivalents per microsporocyte at metaphase I. The frequency of trivalents in the hybrid between T. nigrescens and autotetraploid T. occidentale (2n = 32) was 5.69. The data are interpreted to indicate: (1) a possible autotetraploid origin of T. repens; and (2) a close phylogenetic relationship among T. repens, T. nigrescens and T. occidentale.

MEIOTIC BEHAVIOR OF EXTRA HETEROCHROMATIN IN THE TOMATO: EFFECTS ON SEVERAL VITAL PROCESSES

1976 ◽  
Vol 18 (2) ◽  
pp. 325-337 ◽  
Author(s):  
Carlos F. Quirós
Keyword(s):  
Chromosome Pairing ◽  
Meiotic Prophase ◽  
Interspecific Hybrids ◽  
Constitutive Heterochromatin ◽  
Nucleolar Organizer ◽  
Crossing Over ◽  
Meiotic Behavior ◽  
Tomato Genome ◽  
Leaf Necrosis ◽  
Ectopic Pairing

The cytological behavior during meiosis of extra constitutive heterochromatin and the effects of such additions to the tomato genome were investigated. The main source of extra heterochromatin was 2S∙2S, a completely heterochromatic isochromosome carrying a nucleolar organizer in each of its arms. Meiotic behavior of a half-heterochromatic, tertiary chromosome 5L∙2S in the presence of 2S∙2S was studied. Wehn 2S∙2S chromosomes were present in more than two doses, achiasmatic simultaneous pairing of three, four and five arms of these chromosomes was observed. "Ectopic" pairing of 2S∙2S with heterochromatin of nonhomologous chromosomes was also observed. It is postulated that "ectopic" pairing neutralized in part the high percentage of anaphase I equational division of the 2S∙2S chromosomes. In some individuals the 2S∙2S chromosome was found organizing an extra, smaller-than-normal nucleolus during meiotic prophase. Conspicuous nucleolar vacuoles were also observed in the progenies of plants carrying 2S∙2S extra chromosomes. It was found that the 2S∙2S chromosome alters diakinesis association and segregation of the 5L∙7S chromosome when both are in the same cell. 2S∙2S chromosomes reduced chiasma frequency, which was also accompanied by reduction of crossing-over for some of the tested gene intervals when 2S∙2S was present in one dose. No effects of 2S∙2S on chromosome pairing of interspecific hybrids were detected. Another effect produced by the addition of 2S∙2S chromosomes was expressed as leaf necrosis in some individuals.

scholarly journals Meiotic behavior and fertility of Capsicum interspecific hybrids

2020 ◽  
Vol 38 (4) ◽  
pp. 382-386
Author(s):  
Sara I de Oliveira ◽  
Elba H Ribeiro ◽  
Nádia F Moreira ◽  
Larissa S Vianna ◽  
Telma NS Pereira
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Pollen Viability ◽  
Unreduced Gametes ◽  
Low Fertility ◽  
Gene Pools ◽  
Capsicum Frutescens ◽  
Meiotic Behavior ◽  
Meiotic Abnormality ◽  
Viability Percentage

ABSTRACT This study was performed to evaluate the meiotic behavior and fertility of four hybrids obtained from the crossing of Capsicum baccatum and its botanical forms with Capsicum chinense and Capsicum frutescens. We aimed to identify the causes of the low fertility in interspecific hybrids involving species from different gene pools of Capsicum. Hybrid flower buds were fixed in fixative solution and the slides were prepared using 1%-acetic carmine solution. Meiosis was observed in all phases and the main meiotic abnormality observed was the complete or partial lack of chromosome pairing, indicating that the species are either genetically distant or that some asynaptic gene was present in the hybrids. Meiotic index (MI), the frequency of unreduced gametes (type 2n), and pollen viability were estimated. MI and pollen viability of the hybrids were low. We concluded that due to the complete or partial lack of chromosome pairing, the species used in the hybrid combinations are genetically distant. We also noticed that the low-fertility hybrids are a consequence of the lack of chromosome homology between the two genomes involved. The hybrids were considered partially sterile since their pollen viability percentage was lower than 50%.

THE MEIOTIC BEHAVIOR OF ANEUPOLYHAPLOIDS OF THE CULTIVATED OAT AVENA SATIVA (2n = 6x = 42)

1977 ◽  
Vol 19 (4) ◽  
pp. 651-656 ◽  
Author(s):  
J. M. Leggett
Keyword(s):  
Genetic Control ◽  
Chromosome Pairing ◽  
Avena Sativa ◽  
Meiotic Behavior ◽  
Homoeologous Chromosomes

Chromosome pairing and the frequency of secondary associations in two aneupolyhaploid plants of A. sativa are described. There was little evidence of pairing between homoeologous chromosomes in either plant. The results are discussed in relation to the genetic control of bivalent pairing in A. sativa and the possible divergence between the constituent genomes.

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.

Evidence for genetic suppression of heterogenetic chromosome pairing in polyploidy species of Solanum, sect. Petota

1983 ◽  
Vol 25 (5) ◽  
pp. 530-539 ◽  
Author(s):  
Jan Dvořák
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Diploid Species ◽  
Diploid Hybrid ◽  
Polyploid Species ◽  
Chromosome Differentiation ◽  
Genetic Suppression ◽  
Solanum Sect ◽  
Paradoxical Results

Data on chromosome pairing in haploids and interspecific hybrids of Solanum, sect. Petota reported in the literature were used to determine whether the diploidlike chromosome pairing that occurs in some of the polyploid species of the section is regulated by the genotype or brought about by some other mechanism. The following trends emerged from these data. Most of the polyploid × polyploid hybrids had high numbers of univalents, which seemed to indicate that the polyploid species were constructed from diverse genomes. Haploids, except for those derived from S. tuberosum, had incomplete chromosome pairing. All hybrids from diploid × diploid crosses had more or less regular chromosome pairing, which suggested that all investigated diploid species have the same genome. Likewise, hybrids from polyploid × diploid crosses had high levels of chromosome pairing. These paradoxical results are best explained if it is assumed that (i) the genotypes of most polyploid species, but not those of the diploid species, suppress heterogenetic pairing, (ii) that nonstructural chromosome differentiation is present among the genomes of both diploid and polyploid species, and (iii) the presence of the genome of a diploid species in a polyploid × diploid hybrid results in promotion of heterogenetic pairing. It is, therefore, concluded that heterogenetic pairing in most of the polyploid species is genetically suppressed.

scholarly journals Oligo-painting and GISH reveal meiotic chromosome biases and increased meiotic stability in synthetic allotetraploid Cucumis ×hytivus with dysploid parental karyotypes

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Qinzheng Zhao ◽  
Yunzhu Wang ◽  
Yunfei Bi ◽  
Yufei Zhai ◽  
Xiaqing Yu ◽  
...  
Keyword(s):  
Interspecific Hybridization ◽  
Interspecific Hybrids ◽  
Chromosome Doubling ◽  
Meiotic Chromosome ◽  
Genomic In Situ Hybridization ◽  
Meiotic Behavior ◽  
Cytological Evidence ◽  
Meiotic Stability ◽  
Inbred Family

Abstract Background Meiosis of newly formed allopolyploids frequently encounter perturbations induced by the merging of divergent and hybridizable genomes. However, to date, the meiotic properties of allopolyploids with dysploid parental karyotypes have not been studied in detail. The allotetraploid Cucumis ×hytivus (HHCC, 2n = 38) was obtained from interspecific hybridization between C. sativus (CC, 2n = 14) and C. hystrix (HH, 2n = 24) followed by chromosome doubling. The results of this study thus offer an excellent opportunity to explore the meiotic properties of allopolyploids with dysploid parental karyotypes. Results In this report, we describe the meiotic properties of five chromosomes (C5, C7, H1, H9 and H10) and two genomes in interspecific hybrids and C. ×hytivus (the 4th and 14th inbred family) through oligo-painting and genomic in situ hybridization (GISH). We show that 1) only two translocations carrying C5-oligo signals were detected on the chromosomes C2 and C4 of one 14th individual by the karyotyping of eight 4th and 36 14th plants based on C5- and C7-oligo painting, and possible cytological evidence was observed in meiosis of the 4th generation; 2) individual chromosome have biases for homoeologous pairing and univalent formation in F1 hybrids and allotetraploids; 3) extensive H-chromosome autosyndetic pairings (e.g., H-H, 25.5% PMCs) were observed in interspecific F1 hybrid, whereas no C-chromosome autosyndetic pairings were observed (e.g. C-C); 4) the meiotic properties of two subgenomes have significant biases in allotetraploids: H-subgenome exhibits higher univalent and chromosome lagging frequencies than C-subgenome; and 5) increased meiotic stability in the S14 generation compared with the S4 generation, including synchronous meiosis behavior, reduced incidents of univalent and chromosome lagging. Conclusions These results suggest that the meiotic behavior of two subgenomes has dramatic biases in response to interspecific hybridization and allopolyploidization, and the meiotic behavior harmony of subgenomes is a key subject of meiosis evolution in C. ×hytivus. This study helps to elucidate the meiotic properties and evolution of nascent allopolyploids with the dysploid parental karyotypes.

Evidence for the existence of endosperm balance number in the true clovers (Trifolium spp.)

1986 ◽  
Vol 28 (4) ◽  
pp. 581-586 ◽  
Author(s):  
W. A. Parrott ◽  
R. R. Smith
Keyword(s):  
Ploidy Level ◽  
Related Species ◽  
Interspecific Hybrids ◽  
2N Gametes ◽  
Endosperm Development ◽  
Individual Species ◽  
Interspecific Crosses ◽  
Endosperm Balance Number ◽  
Endosperm Tissue ◽  
2N Eggs

The endosperm balance number (EBN) hypothesis was first advanced to explain results from interspecific crosses in Solanum and later in Impatiens. According to the EBN hypothesis, normal endosperm development following intra- or inter-specific crosses depends on having a ratio of two EBNs from the female to one EBN from the male in the endosperm tissue. EBNs may differ among related species. Successful hybrids can be obtained between species with the same EBN. The ploidy level of an individual species can be varied to modify its EBN, making it cross compatible with a species sharing its modified EBN. Interspecific crosses within Trifolium have been limited and difficult. Crosses reported in the literature, including evidence from our own study, suggest that EBN is operating in Trifolium and have been used to assign EBN numbers to some clover species. The use of 2n eggs enabled two species, differing in EBN, to be crossed. An understanding of the EBN mechanism that operates in Trifolium should make successful interspecific hybrids easier to obtain in the future.Key words: endosperm balance number, hybrids (interspecific), 2n gametes, Trifolium.

Genome constitution of the Australian hexaploid grass Elymus scabrus (Poaceae: Triticeae)

Genome ◽  
1993 ◽  
Vol 36 (1) ◽  
pp. 147-151 ◽  
Author(s):  
J. Torabinejad ◽  
R. J. Mueller
Keyword(s):  
Chromosome Pairing ◽  
Interspecific Hybrids ◽  
Intergeneric Hybrid ◽  
Meiotic Pairing ◽  
Genome Constitution ◽  
Psathyrostachys Juncea ◽  
Hybrid Plants ◽  
Thinopyrum Bessarabicum ◽  
Mother Cells ◽  
Metaphase I

Eight intergeneric hybrid plants were obtained between Elymus scabrus (2n = 6x = 42, SSYY??) and Australopyrum pectinatum ssp. retrofractum (2n = 2x = 14, WW). The hybrids were vegetatively vigorous but reproductively sterile. Examination of pollen mother cells at metaphase I revealed an average of 16.63 I, 5.29 II, 0.19 III, and 0.05 IV per cell for the eight hybrids. The average chiasma frequency of 6.77 per cell in the above hybrids strongly supports the presence of a W genome from A. pectinatum ssp. retrofractum in E. scabrus. Meiotic pairing data of some other interspecific hybrids suggest the existence of the SY genomes in E. scabrus. Therefore, the genome constitution of E. scabrus should be written as SSYYWW. Two other hybrid plants resulted from Elymus yezoensis (2n = 4x = 28, SSYY) crosses with A. pectinatum ssp. pectinatum (2n = 2x = 14, WW). Both were weak and sterile. An average of 0.45 bivalents per cell were observed at metaphase I. This clearly indicates a lack of pairing between W genome of Australopyrum and S or Y genomes of E. yezoensis. In addition, six hybrid plants of E. scabrus with Psathyrostachys juncea (2n = 2x = 14, NN) and one with Thinopyrum bessarabicum (2n = 2x = 14, JJ) were also obtained. The average bivalents per cell formed in both combinations were 2.84 and 0.70, respectively. The results of the latter two combinations showed that there is no N or J genome in E. scabrus.Key words: wide hybridization, chromosome pairing, genome analysis, Australopyrum, Elymus.

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