Early adjustment of patterns of metaphase association in the evolution of a polyploid species

Ingram, Richard; Noltie, H. J.

doi:10.1007/bf00058670

Cited by 10 publications

(7 citation statements)

References 8 publications

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“…Ingram and Noltie (1989) conclude that the stability of the autoallopolyploid is due to the meiotic regularity of the autotetraploid S. vulgaris. Senecio cambrensis (2n = 60) is an established autoallohexaploid derived from the diploid S. sqalidus (2x = 20) and the relatively recent autotetraploid S. vulgaris (4x = 40).…”

Section: Adjusting Chromosome Pairing Differentiationmentioning

confidence: 76%

“…The example given by Mursal and Endrizzi (1976) has been discussed above. Also discussed above is the autoallohexaploid Senecio cambrensis (Ingram and Noltie 1989). The reconstruction was meiotically less regular than the established polyploid, although the auto tetraploid parent S. vulgaris used was quite stable.…”

Section: Reconstruction Of Existing Allopolyploidsmentioning

confidence: 99%

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Cytogenetics in Plant Breeding

Sybenga

1992

Monographs on Theoretical and Applied Genetics

109

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Section: Adjusting Chromosome Pairing Differentiationmentioning

confidence: 76%

Section: Reconstruction Of Existing Allopolyploidsmentioning

confidence: 99%

Cytogenetics in Plant Breeding

Sybenga

1992

Monographs on Theoretical and Applied Genetics

109

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“…Because many polyploid species originate on more than one occasion and at different locations (Soltis & Soltis, 1993), the study of polyploid speciation can be replicated in the wild. Moreover, it is often feasible to resynthesize artificially new polyploids from their known parents (Levin, 2002) and subject synthetic material to detailed comparative analysis (Ingram & Noltie, 1989). Although it appears obvious that newly originated polyploid species provide an excellent resource for studying the process of polyploid speciation in detail, such species have until now been underused for this purpose.…”

Section: Introductionmentioning

confidence: 99%

Origins, establishment and evolution of new polyploid species: Senecio cambrensis and S. eboracensis in the British Isles

Abbott

Lowe

2004

Biological Journal of the Linnean Society

189

165

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Two new polyploid species of Senecio have originated in the British Isles in recent times following hybridization between native S. vulgaris (2 n = 40) and introduced S. squalidus (2 n = 20). One of these is the allohexaploid S. cambrensis (2 n = 60), the other is the recombinant tetraploid S. eboracensis (2 n = 40). We review what is known about when and how each species originated, and their reproductive isolation from parents due to high selfing rates. We also review evidence that suggests S. cambrensis may have undergone rapid genome evolution since its origin, and comment on the risks of extinction to each species due to chance factors operating during the early establishment phase. The discovery of both species soon after their origin provides an unparalleled opportunity to examine two different but related forms of speciation following hybridization between the same parent species. Further detailed study of the ecology and genomics of S. cambrensis and S. eboracensis will help improve our understanding of the process of polyploid speciation in plants.

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“…The marked similarity in the size and distribution of C-bands within groups of assumed homoeologous chromosomes suggests that close homology may have existed at some point between the diploid progenitors of this species. It is possible that differences in chromosome size between the diploid sets of a new tetraploid may promote diploidization, which as Ingram and Noltie (1989) point out, is likely to occur early in the establishment of a new polyploid, leading to the enhancement of fertility.…”

Section: Discussionmentioning

confidence: 98%

Karyological analysis and genome size in Milium (Gramineae) with special reference to polyploidy and chromosomal evolution

Bennett¹,

Thomas²

1991

Genome

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BENNETT, S. T., and THOMAS, S. M. 1991. Karyological analysis and genome size in Milium (Gramineae) with special reference to polyploidy and chromosomal evolution. Genome, 34: 868-878. Karyotypes, nuclear DNA amounts, and meiotic behaviour are presented for Milium effusum L. (2n = 28), Milium montianum Parl. (2n = 22), and two cytotypes of Milium vernale Bieb. (2n = 8, 10). The bimodal karyotype of M. montianum (8 large and 14 small chromosomes) is described for the first time. Evidence from C-banding and geographical distribution suggests an ancient interracial allopolyploid origin for M. effusum (2n = 28). Although M. montianum is undoubtedly allopolyploid, its parentage is unconfirmed. A strong resemblance between the M. vernale (2n = 8) karyotype and the eight large chromosomes in M. montianum suggests a common ancestry. It is possible that a diploid form of M. effusum contributed the remaining 14 chromosomes. A selective loss of DNA sequences from the smaller chromosomes during the subsequent reorganization of the allopolyploid genome may have enhanced the bimodality of the karyotype. Geographical distribution and a change in the breeding system support the direction of the change x = 5 to x = 4 in M. vernale. Allopolyploidy appears to have played a central role in the chromosome evolution and speciation of Milium. Key words: Milium (Gramineae), karyotype analysis, genome size, polyploidy, chromosome evolution. BENNETT, S. T., et THOMAS, S. M. 1991. Karyological analysis and genome size in Milium (Gramineae) with special reference to polyploidy and chromosomal evolution. Genome, 34 : 868-878. La presente etude a porte sur les caryotypes, les quantites d'ADN nucleaire et le comportement meiotique des entites suivantes : Milium effusum L. (2n = 28), Milium montianum Parl. (2n = 22), et deux cytotypes de Milium vernale Bieb. (2n = 8, 10). Le caryotype bimodal de M. montianum (8 grands et 14 petits chromosomes) est decrit pour la premiere fois. Les evidences provenant de la distribution geographique et des bandes C suggerent pour le M. effusum (2n = 28) une origine allopolyploi'de interraciale. Le M. montianum est probablement allopolyploi'de, mais ses origines ancestrales n'ont pas ete confirmies. La forte resemblance existant entre le caryotype de M. vernale (2n = 8) et les huit gros chromosomes du M. montianum suggere pour ces deux entites une origine ancestrale commune. 11 est possible qu'une forme diploi'de de M. effusum ait pu fournir les 14 autres chromosomes. Une perte selective de sequences d'ADN chez les plus petits chromosomes lors d'une reorganisation subsequente du genome allopoiyploi'de peut avoir favorise la bimodalite de ce caryotype. La distribution geographique et un systeme de croisements vient a l'appui de la direction du changement de x = 5 a x = 4 chez le M. vernale. L'allopolyploi'die semble avoir joue un r81e dominant dans l'evolution chromosomique et la speciation chez le Milium.

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Early adjustment of patterns of metaphase association in the evolution of a polyploid species

Cited by 10 publications

References 8 publications

Cytogenetics in Plant Breeding

Cytogenetics in Plant Breeding

Origins, establishment and evolution of new polyploid species: Senecio cambrensis and S. eboracensis in the British Isles

Karyological analysis and genome size in Milium (Gramineae) with special reference to polyploidy and chromosomal evolution

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