Interspecific manipulation of chromosomes

1981 ◽  
Vol 292 (1062) ◽  
pp. 519-527 ◽  
Keyword(s):  
Chromosome Pairing ◽  
Genetic System ◽  
Alien Chromosome ◽  
Polyploid Species ◽  
Crop Species ◽  
Chromosome Manipulation ◽  
Alien Gene ◽  
Species Hybrids ◽  
Similar Gene ◽  
Pairing Behaviour

The success of introducing alien variation into crop species from related species depends on the cytogenetic relations between the species. If there are no restrictions on chromosome pairing and recombination in species hybrids, a backcrossing programme can be used to obtain the desired gene transfers. However, when there is a failure of adequate chromosome pairing in species hybrids, techniques of chromosome manipulation have to be used to obtain alien gene transfers. In polyploid crop species it is possible to introduce appropriate single chromosomes of the alien species into the genotype of the recipient species, but the failure of the alien chromosome to become integrated into the genotype of the recipient species often leads to meiotic instability. The introduction of segments of alien chromosomes has been successful through the use of irradiation-induced translocations. The deletions/duplications that are a consequence of such translocations do limit the usefulness of this approach. In a number of allopolyploid crop species, regular bivalent pairing behaviour has been shown to be genetically controlled. By interfering with the genetic system controlling the diploid-like pairing it is possible to induce pairing between the alien chromosomes and its corresponding chromosomes in the crop species. Gene transfers based on this method involve exchanges between chromosomes of similar gene sequences. These techniques are discussed and application of the procedures to transfer alien variation into the cultivated oat is described. A scheme is also proposed for transferring the genes controlling regular bivalent pairing from natural polyploid species into synthetic amphiploids in Lolium/Festuca .

Synthesis and cytological characterization of trigeneric hybrids of durum wheat with and without Ph1

Genome ◽  
2004 ◽  
Vol 47 (6) ◽  
pp. 1173-1181 ◽  
Author(s):  
Prem P Jauhar ◽  
M Doğramaci ◽  
T S Peterson
Keyword(s):  
In Situ Hybridization ◽  
Chromosome Pairing ◽  
Genetic Recombination ◽  
Genomic In Situ Hybridization ◽  
Homoeologous Pairing ◽  
Alien Gene Transfer ◽  
Chromosome 5B ◽  
Alien Gene ◽  
Trigeneric Hybrids

Wild grasses in the tribe Triticeae, some in the primary or secondary gene pool of wheat, are excellent reservoirs of genes for superior agronomic traits, including resistance to various diseases. Thus, the diploid wheatgrasses Thinopyrum bessarabicum (Savul. and Rayss) Á. Löve (2n = 2x = 14; JJ genome) and Lophopyrum elongatum (Host) Á. Löve (2n = 2x = 14; EE genome) are important sources of genes for disease resistance, e.g., Fusarium head blight resistance that may be transferred to wheat. By crossing fertile amphidiploids (2n = 4x = 28; JJEE) developed from F1 hybrids of the 2 diploid species with appropriate genetic stocks of durum wheat, we synthesized trigeneric hybrids (2n = 4x = 28; ABJE) incorporating both the J and E genomes of the grass species with the durum genomes A and B. Trigeneric hybrids with and without the homoeologous-pairing suppressor gene, Ph1, were produced. In the absence of Ph1, the chances of genetic recombination between chromosomes of the 2 useful grass genomes (JE) and those of the durum genomes (AB) would be enhanced. Meiotic chromosome pairing was studied using both conventional staining and fluorescent genomic in situ hybridization (fl-GISH). As expected, the Ph1-intergeneric hybrids showed low chromosome pairing (23.86% of the complement), whereas the trigenerics with ph1b (49.49%) and those with their chromosome 5B replaced by 5D (49.09%) showed much higher pairing. The absence of Ph1 allowed pairing and, hence, genetic recombination between homoeologous chromosomes. Fl-GISH analysis afforded an excellent tool for studying the specificity of chromosome pairing: wheat with grass, wheat with wheat, or grass with grass. In the trigeneric hybrids that lacked chromosome 5B, and hence lacked the Ph1 gene, the wheat–grass pairing was elevated, i.e., 2.6 chiasmata per cell, a welcome feature from the breeding standpoint. Using Langdon 5D(5B) disomic substitution for making trigeneric hybrids should promote homoeologous pairing between durum and grass chromosomes and hence accelerate alien gene transfer into the durum genomes.Key words: alien gene transfer, chiasma (xma) frequency, chromosome pairing, fluorescent genomic in situ hybridization (fl-GISH), homoeologous-pairing regulator, specificity of chromosome pairing, wheatgrass.

CHROMOSOME DIFFERENTIATION IN POLYPLOID SPECIES OF ELYTRIGIA, WITH SPECIAL REFERENCE TO THE EVOLUTION OF DIPLOID-LIKE CHROMOSOME PAIRING IN POLYPLOID SPECIES

1981 ◽  
Vol 23 (2) ◽  
pp. 287-303 ◽  
Author(s):  
J. Dvořák
Keyword(s):  
Triticum Aestivum ◽  
Special Reference ◽  
Normal Level ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Triticum Aestivum L ◽  
Polyploid Species ◽  
Chromosome Differentiation

Triticum aestivum L. em Thell ditelosomics 7AL and 7DS and T. aestivum-Elytrigia elongata (Host) Holub (2n = 2x = 14) ditelosomic additions were crossed with "E. elongata 4x" (2n = 4x = 28), E. caespitosa (C. Koch) Nevski (2n = 4x = 28), and E. intermedia (Host) Nevski (2n = 6x = 42). The effect of each Elytrigia genotype on homoeologous (heterogenetic) chromosome pairing was assessed by comparing the pairing frequencies of T. aestivum cv. Chinese Spring telosomes 7AL and 7DS in the hybrids with the pairing frequency of telosome 7AL in haploid Chinese Spring. The genotype of "E. elongata 4x" had no effect on heterogenetic pairing in the hybrids. Although some genotypes of E. caespitosa and E. intermedia promoted heterogenetic pairing in the hybrids, others had no effect. Telosome VS of E. elongata interacted in a complementary fashion with the genotype of "E. elongata 4x," but not with the genotypes of Chinese Spring and E. caespitosa, and it promoted heterogenetic pairing. In hybrids in which the wheat diploidizing genes were active at the normal level, the E. elongata telosomes paired with chromosomes of "E. elongata 4x" in 5.8% to 24.6% of the cells, with chromosomes of E. caespitosa in 0.0% to 1.0% of the cells, and with chromosomes of E. intermedia in 0.0% to 2.8% of the cells. A model of chromosome differentiation is discussed and special attention is devoted to the origin of diploid-like pairing in polyploid species.

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.

Chromosome pairing in Oryza sativa L. × O. latifolia Desv. hybrids

1986 ◽  
Vol 28 (2) ◽  
pp. 278-281 ◽  
Author(s):  
E. M. Nowick
Keyword(s):  
Oryza Sativa ◽  
Chromosome Pairing ◽  
Embryo Culture ◽  
Oryza Sativa L ◽  
Meiotic Chromosome ◽  
Genetic System ◽  
Meiotic Chromosome Pairing

Meiotic chromosome pairing was examined in F1 hybrid regenerants from Oryza sativa (AA) × O. latifolia (CCDD) and O. glumaepatula (AcuAcu) × O. latifolia (CCDD) crosses produced through embryo culture. The average number of chromosome pairs in the O. sativa × O. latifolia regenerants ranged from 13.79 to 14.79. Ten to 18 bivalents were observed per cell. The average number of bivalents in the O. glumaepatula × O. latifolia regenerants ranged from 12.44 to 13.87, with 10–17 bivalents per cell. Some desynapsis occurred but 10 to 12 true bivalents remained at late metaphase in most cells. The high number of bivalents observed in the hybrids from these divergent parents indicates that a genetic system for pairing control similar to that in Triticum may be present in the Oryza genus.Key words: Oryza, embryo culture, meiosis.

Tetrasomic inheritance and chromosome pairing behaviour in the naturally occurring autotetraploid Heuchera grossulariifolia (Saxifragaceae)

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 655-659 ◽  
Author(s):  
Paul G. Wolf ◽  
Pamela S. Soltis ◽  
Douglas E. Soltis
Keyword(s):  
Chromosome Pairing ◽  
Meiotic Chromosome ◽  
Low Frequency ◽  
Small Chromosome ◽  
Tetrasomic Inheritance ◽  
Naturally Occurring ◽  
Chromatid Segregation ◽  
Marker Loci ◽  
Allozyme Loci ◽  
Pairing Behaviour

Inheritance patterns at four allozyme loci and chromosome pairing behaviour at diakinesis were examined in the naturally occurring autotetraploid Heuchera grossulariifolia. Segregation patterns for Tpi, Pgi, Pgm-2, and Lap deviated significantly from all possible disomic models. All patterns were consistent with tetrasomic inheritance of these marker loci. No chromatid segregation was detected electrophoretically. Meiotic chromosome configurations at diakinesis in 45 cells were compared with a previously published model to test for autopolyploid-like chromosome pairing. Using the observed chiasma frequencies, the frequency of quadrivalents was consistent with the expectations for an autotetraploid. We suggest that the low frequency of quadrivalents at diakinesis in Heuchera grossulariifolia is due to small chromosome size, which results in a low chiasma frequency.Key words: autopolyploidy, tetrasomic inheritance, chromosome pairing, isozyme genetics, Heuchera.

scholarly journals Meiosis in Oenothera missouriensis

1933 ◽  
Vol 113 (780) ◽  
pp. 57-70 ◽  
Keyword(s):  
Chromosome Pairing ◽  
Cytological Study ◽  
Stage Ii ◽  
Species Hybrid ◽  
Final Solution ◽  
Pollen Mother Cells ◽  
Closed Circle ◽  
Somatic Number ◽  
Mother Cells ◽  
Species Hybrids

A cytological study of the meiotic phenomena in Oenothera may not need an excuse in spite of the exhaustive studies of the genus made by numerous competent cytologists of this century. Up to the present time, all the investigators of Oenothera cytology have been successful in establishing that the basic ( n ) number of chromosomes in this genus is 7; although tetraploid (Gates, 1911), triploid (Cathcheside, 1931), and trisomic numbers might occur either naturally (by mutation) or could be produced by experiment. It is also known that the somatic number of chromosomes corresponds with the number of chromosome bodies in the diakinesis and metaphase of the heterotypic division.. Thus in diploid Oenothera species, hybrid, or mutant at the diakinesis of pollen mother cells 14 chromosomes have been shown to exist, withouth any doubt, in the configuration of a closed circle, in 7 ring pairs, or a mixtrue of free pairs and closed circles. Mathematically, there are 15 possible configurations in which 14 chromosomes can arrange themselves in the form of closed circle, ring pairs, or a combination of ring pairs and closed circles (Cleland and Blakeslee, 1931; Darlington, 1931). Of these 15 Possible configurations 13 have already been reported in various Oenothera species, hybrids and mutants (Darlington, 1931). Regarding the origin and significance of these chromosome configurations invsestigators have not yet reached an agreed opinion. Apart from the genetical significance, the much disputed cytological question of parasynaptic and telosynaptic methods of chromosome pairing is yet far from a final solution. In oenothera both the methods of pairing have strong sup-porters in consideration of observed cytological facts. The fact are (i) the continuous spireme (in leptotene stage); (ii) the pachynema and the diakinesis consisting of the 14 chromosomes arranged end to end. This arragement, known as catenation of chromosomes, favours the telosynaptic rather than the parasynaptic union. Wheras (i) double threads at the prophase, (ii) the looping of the threads, and (iii) the half number of bodies (7 ring pairs) at the diakinesis support the parasynaptic method of pairing of chromosomes. The occurence of a complete catenation of 14 chromosomes in some Oenotheras and the presence of 7 free pairs in others naturally suggests the question-whether they can be correlated with the two methods of chromosome-pairing in the meiosis of Oenothera .

GENETIC REGULATION OF HETEROGENETIC CHROMOSOME PAIRING IN POLYPLOID SPECIES OF THE GENUS TRITICUM sensu lato

1982 ◽  
Vol 24 (1) ◽  
pp. 57-82 ◽  
Author(s):  
Patrick E. McGuire ◽  
Jan Dvořák
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Genetic Regulation ◽  
Triticum Aestivum L ◽  
Polyploid Species ◽  
D Genome ◽  
Chromosome 5B ◽  
A Genome

Polyploid species of Triticum sensu lato were crossed with Triticum aestivum L. em. Thell. cv. Chinese Spring monotelodisomics or ditelosomics that were monosomic for chromosome 5B. Progeny from these crosses were either euploid, nullisomic for 5B, monotelosomic for a given Chinese Spring chromosome, or nullisomic for 5B and monotelosomic simultaneously. The Chinese Spring telosome in the hybrids permitted the evaluation of autosyndesis of chromosomes of the tested species. In addition, several Chinese Spring eu- and aneuhaploids were produced. Genotypes of T. cylindricum Ces., T. juvenale Thell., T. triunciale (L.) Raspail, T. ovatum (L.) Raspail, T. columnare (Zhuk.) Morris et Sears, T. triaristatum (Willd.) Godr. et Gren., and T. rectum (Zhuk.) comb. nov. were all shown to have suppressive effects on heterogenetic pairing in hybrids lacking 5B or 3AS, whereas T. kotschyi (Boiss.) Bowden had no effect. It was concluded that diploid-like meiosis in these species is due to genetic regulation. A number of these genotypes promoted heterogenetic pairing in the presence of 5B. A model is presented to explain this dichotomous behavior of the tested genotypes. Monotelosomic-3AL haploids had a greater amount of pairing than did euhaploid Chinese Spring, which substantiated the presence of a pairing suppressor(s) on the 3AS arm. Evidence is presented that shows that T. juvenale does not have a genome homologous with the D genome of T. aestivum.

Cytology of species hybrids in the Setaria sphacelata complex

1968 ◽  
Vol 16 (3) ◽  
pp. 551 ◽  
Author(s):  
JB Hacker
Keyword(s):  
Chromosome Pairing ◽  
Setaria Sphacelata ◽  
Close Relationship ◽  
Relationship Of ◽  
Species Hybrids ◽  
Very High

Hybrids were produced between diploid strains of Setaria anceps, S. trinervia, tetraploid strains of S. anceps and S. splendida, and hexaploid strains of all three species. Very high levels of chromosome pairing at meiosis indicate close relationship of the different species and throw doubt on the validity of their separation. It is probable that characters from S. trinervia and S. splendida may be incorporated in the commercially useful S. anceps without too much difficulty.

scholarly journals The position of a locus on chromosome 5B of Triticum aestivum affecting homoeologous meiotic pairing

1971 ◽  
Vol 18 (3) ◽  
pp. 329-339 ◽  
Author(s):  
A. M. Wall ◽  
Ralph Riley ◽  
M. D. Gale
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Single Locus ◽  
Meiotic Pairing ◽  
Homoeologous Pairing ◽  
Chromosome 5B ◽  
Homoeologous Chromosome Pairing ◽  
Mutant Locus ◽  
Homoeologous Chromosomes ◽  
Pairing Behaviour

SUMMARYAn investigation was made of the chromosomal position of the mutant locus, in Mutant 10/13 of Triticum aestivum (2n = 6x = 42), affecting homoeologous chromosome pairing at meiosis. In hybrids between Mutant 10/13 and rye (Secale cereale 2n = 14), homoeologous chromosomes frequently pair at meiosis although normally, in wheat-rye hybrids, this happens infrequently.The association of the mutant condition with chromosome 5B was determined by (i) the absence of segregation in hybrids obtained when Mutant 10/13 monosomic 5B was pollinated by rye; (ii) the occurrence of trisomie segregation for pairing behaviour in 28-chromosome wheat-rye hybrids, obtained from SB trisomie wheat parents with two 5B chromosome from a non-mutant and one from a mutant parent; (iii) the absence of segregation for pairing behaviour in the 29-chromosome wheat-rye hybrids obtained from the same trisomie wheat parents.The alternative pairing behaviours segregated independently of the centromere when wheat plants that were simultaneously heteromorphic, 5BL telocentric/5B complete, and heterozygous for the Mutant 10/13 state, were pollinated by rye. The alternative chromosome-pairing patterns segregated to give a ratio not different from 1:1, so that the association of homoeologous pairing with Mutant 10/13 probably derived from the occurrence of mutation at a single locus on 5BL. In the disomic heteromorphic state, 5BL was 91 map units in length.Trisomie wheats with two complete 5B chromosomes and one 5BL telocentric, that were also heterozygous for the Mutant 10/13 condition, were pollinated by rye. Among the resulting 28-chromosome hybrids there was a 2:1 segregation of hybrids with low pairing: high (homoeologous) pairing and also of hybrids with complete 5B: telocentric 5BL. However, there was no evidence of linkage in this trisomie segregation. All the 29-chromosome hybrids from this cross had low pairing and it could be concluded that the single mutant allele, in Mutant 10/13, was recessive. In the trisomie condition, relative to a simplex situation, 5BL was 33·05 map units in length.The critical locus on 5BL was designated Pairing homoeologous. The normal dominant allele was symbolized Ph and the recessive allele, in Mutant 10/13, ph.The prevention of homoeologous pairing by the activity of a single locus makes the evolution of the regular meiotic behaviour of T. aestivum more readily comprehensible.

Identification of a diploidizing genotype of Lolium multiflorum

1985 ◽  
Vol 27 (5) ◽  
pp. 498-505 ◽  
Author(s):  
G. M. Evans ◽  
Taing Aung
Keyword(s):  
Mathematical Models ◽  
Chromosome Pairing ◽  
Interspecific Hybrid ◽  
Lolium Multiflorum ◽  
Hybrid Progeny ◽  
Single Plant ◽  
Homoeologous Chromosome ◽  
High Incidence ◽  
Species Hybrids ◽  
Diploid Populations

Thirty diploid populations of Lolium multiflorum were screened for genes that were capable of modifying meiosis in species hybrids. A standard genotype of L. temulentum was used as the tester species. Modified pairing at first metaphase of meiosis was identified in some of the hybrid progeny of a single plant from a population from Uruguay and also in one from Portugal. Evidence is presented to show that the high incidence of univalents in diploid hybrids of L. temulentum × L. multiflorum from Uruguay was due to the suppression of homoeologous chromosome association only. A proportion of equivalent triploid and tetraploid hybrids had an excess of bivalents at first metaphase of meiosis. This was confirmed by comparison of the observed meiotic data with that expected from three separate mathematical models. It is concluded that this single plant from the Uruguayan population was heterozygous for genes that suppress chiasmate association of homoeologous chromosomes.Key words: interspecific hybrid, Lolium, chromosome pairing.

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