Asynapsis und Ihre Bedeutung f�r die Genomanalyse

Gaul, H.

doi:10.1007/bf00308437

Cited by 10 publications

(3 citation statements)

References 91 publications

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“…Investigators applying genome analysis to interspecific hybrids must recognize that the axiom that homologous chromosomes pair and non-homologous chromosomes do not is by no means absolute. Genes controlling synapsis may prevent pairing of complete homologs (Gaul, 1954), whereas completely non-homologous chromosomes may pair illegitimately (Reiger, 1957). Possible disharmonious gene interactions (Pope and Love, 1952) or genetic imbalance due to hemizygosity (Dewey,19(3) in hybrids might also affect chromosome pairing.…”

Section: ' \mentioning

confidence: 99%

Genome Analysis of Agropyron Repens × Agropyron Cristatum Synthetic Hybrids

Dewey

1964

American J of Botany

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Hexaploid A. repens, 2n = 42, and diploid A. cristatum, 2n = 14, were hybridized and gave rise to two 28‐chromosome reciprocal hybrids. Approximately 1% of hand‐emasculated florets of both parent species produced viable hybrid seed following controlled pollination. Early embryo abortion prevented greater hybrid seed set on A. repens, whereas failure of fertilization appeared to be the major cause of poor hybrid seed set on A. cristatum. Reciprocal differences in hybrid vegetative and spike morphology were striking. The A. repens × A. cristatum hybrid was vigorous, highly rhizomatous, and bore abundant spikes whose morphology was intermediate between that of the parent species. A. cristatum × A. repens hybrids were weak, non‐rhizomatous with frequently‐malformed spikes. Mean chromosome associations of 0.10 I, 20.10 II, and 0.43 IV were observed in 134 metaphase‐I cells of A. repens. Subsequent meiotic stages were regular except for occasional laggards and bridges at anaphase I and II. Metaphase‐I chromosome associations averaged 0.07 I and 6.97 II in 124 A. cristatum cells. Chromosome pairing in the hybrids was highly variable and averaged 11.45 I, 7.58 II, 0.44 III, and 0.02 IV per cell in 187 cells interpreted. From 5 to 14 laggards appeared in every hybrid cell at anaphase I. Bridges were observed in approximately 25% of the anaphase‐I cells. Similar irregularities were observed at anaphase II. Pollen viability was estimated as 3%, and the hybrids failed to set viable seed. On the basis of chromosome pairing in the species itself and in the hybrids, A. repens was designated as a segmental autoallohexaploid with a genome formula of the type A1A1A2A2BB. Although A. repens and A. cristatum chromosomes paired occasionally, the genomes of the 2 species were essentially non‐homologous. Some of the interpretational difficulties of genome analysis were discussed.

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confidence: 99%

Genome Analysis of Agropyron Repens × Agropyron Cristatum Synthetic Hybrids

Dewey

1964

American J of Botany

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“…It may also reflect the action of one or a few genes, which are capable of obscuring close genomic relationships. This hazard of genome analysis has been discussed among others by Gaul ( 1954). Several of the hexaploid species of Geum sect.…”

Section: Natural Relationshipmentioning

confidence: 99%

Genetic and Taxonomic Studies in Gilia. XI. Fertility Relationships of the Diploid Cobwebby Gilias

Grant¹,

Grant²

1960

aliso

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“…The effect of genetical and environmental factors on pairing distributions must also be considered. GAUL (1954) developed the following formula for determining the number of chromosomes p which are able to pair: X 2 + X -B p = (2X-B)Z where X, B and Z are the total observed numbers of chiasmata, of paired chromosomes and the number of cells in the particular preparation, respectively. However, if the number of chiasmata per bivalent cannot be recognized, GAUL'S formula is not applicable.…”

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Statistical Analysis of Chromosome Pairing in Interspecific Hybrids. I. The Probability Distributions

Sficas

1962

Genetics

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Asynapsis und Ihre Bedeutung f�r die Genomanalyse

Cited by 10 publications

References 91 publications

Genome Analysis of Agropyron Repens × Agropyron Cristatum Synthetic Hybrids

Genome Analysis of Agropyron Repens × Agropyron Cristatum Synthetic Hybrids

Genetic and Taxonomic Studies in Gilia. XI. Fertility Relationships of the Diploid Cobwebby Gilias

Statistical Analysis of Chromosome Pairing in Interspecific Hybrids. I. The Probability Distributions

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