Nucleolar suppression, its inheritance and association with taxonomy and sex in the genus Ribes

Keep, Elizabeth

doi:10.1038/hdy.1971.55

Cited by 5 publications

(1 citation statement)

References 30 publications

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“…Normally they remain latent and only in some changed physical and/or genetic environment they might get activated (Jain, 1957;Snoad, 1956;Levin, 1973). Often in species hybrids and allopolyploids the normal organizer of one of the species involved, is suppressed (Navashin, 1927(Navashin, , 1934Keep, 1962Keep, , 1971Yeh& Peloquin, 1965). The nucleolar organizers as in Crotalaria show variation at interspecific or even at interplant level (Dyer, t964;Jones, 1964;Raina & Khoshoo, 1971;Raina & Verma, 1979).…”

Section: Agatiflora Growing Wild In Ethiopia and Eastmentioning

confidence: 99%

Cytogenetics of Crotalaria V. Supernumerary nucleoli in C. agatiflora (Leguminosae)

Verma

Raina

1981

Genetica

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Of 35 species of Crotalaria (Leguminosae) studied, all but one had usually one nucleolus in the premetaphase I cells. In C. agatiflora 300 PMCs from four out of five plants were investigated and the percentage cells with more than one nucleolus was determined as well as the nature of nucleolar attachment to bivalents and the range and the sizes of various nucleoli present in the cell. The "aberrant' cells ranged from 42 to 50%. The nucleoli (1-6) were usually attached to different bivalents. Where one nucleolus was present in the cell, it was always attached to an X-shaped bivalent, formed of a pair of nucleolar chromosomes. In the aberrant cells one nucleolus usually was attached to such a bivalent. The presence of accessory nucleoli has been attributed to hybridity as a result of large-scale intercrossing among five subspecies and consequent dispersal of intermediates in the adjoining areas where C. agatflora grows wild (East Africa and Ethiopia).The change in the regulatory system of the cell caused by hybridity results in activation of latent nucleolar organizers, although their overall presence in the genome is not due to hybridity.

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Section: Agatiflora Growing Wild In Ethiopia and Eastmentioning

confidence: 99%

Cytogenetics of Crotalaria V. Supernumerary nucleoli in C. agatiflora (Leguminosae)

Verma

Raina

1981

Genetica

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‘Nucleolar dominance’ as observed in barley translocation lines with specifically reconstructed SAT chromosomes

Nicoloff

Anastassova-Kristeva

Rieger

et al. 1979

Theoret. Appl. Genetics

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Diploid homo- and heterokaryotypes of barley translocation lines with only one satellite chromosome pair containing two nucleolus organizer regions (NORs) in opposite arms were found to show repressed nucleolus formation by the transposed NOR as evident from the formation of only micronucleoli. The same was true for auto-tetraploid homokaryotypes and for translocation lines with all NORs tandemly arranged into the same chromosome arm. When NORs were transposed to chromosomes without NOR in the standard karyotype, the normal pattern of nucleolus formation remained unaffected. The modified mode of nucleolus formation after the combination of all NORs in one chromosome pair is interpreted to be due to intrachromosomal nucleolar dominance analogous to interchromosomal nucleolar dominance observed in certain interspecific hybrids.

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Accessory nucleoli in microsporocytes of hybrid Phlox

Levin

1973

Chromosoma

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Nucleolar suppression, its inheritance and association with taxonomy and sex in the genus Ribes

Cited by 5 publications

References 30 publications

Cytogenetics of Crotalaria V. Supernumerary nucleoli in C. agatiflora (Leguminosae)

Cytogenetics of Crotalaria V. Supernumerary nucleoli in C. agatiflora (Leguminosae)

‘Nucleolar dominance’ as observed in barley translocation lines with specifically reconstructed SAT chromosomes

Accessory nucleoli in microsporocytes of hybrid Phlox

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