Pairing competition between metacentric and telocentric chromosomes in autotetraploid rye

Benavente, Elena; Orellana, Juan

doi:10.1038/hdy.1989.47

Cited by 8 publications

(3 citation statements)

References 20 publications

(12 reference statements)

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“…Possible preferences between chromosomes of a tetrasome were inferred from analyses to determine the segregation of genetic and/or chromosomal markers (Giraldez and Santos, 1981; Santos et al, 1983; Benavente and Orellana, 1991; Curole and Hedgecock, 2005). The most exhaustive cytological studies were conducted on rye, taking advantage of the existence of C-bands polymorphisms, especially in the nucleolar organizing region (NOR)-bearing chromosome 1R (Orellana and Santos, 1985; Benavente and Orellana, 1989, 1991; Benavente and Sybenga, 2004). In general, in this species there is a trend to identical over homologous preferential associations at metaphase I.…”

Section: Introductionmentioning

confidence: 99%

Competition for Chiasma Formation Between Identical and Homologous (But Not Identical) Chromosomes in Synthetic Autotetraploids of Arabidopsis thaliana

2019

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Polyploid organisms provide additional opportunities to study meiosis in a more complex context since more than two potential homologous chromosomes are available. When the chromosome complement of a diploid individual is duplicated, each chromosome is accompanied by one identical and two homologous chromosomes within the same nucleus. In this situation, a competition in pairing/synapsis/chiasma formation between identical and homologous (but not necessarily identical) chromosomes can occur. Several studies have been conducted in different species to address whether there are preferences in crossover formation between identical rather than homologous chromosomes. In this study, multivalent and chiasma frequencies were cytologically analyzed in synthetic autotetraploids of Arabidopsis thaliana including the accessions Col, Ler, and the Col/Ler hybrid. Fluorescence in situ hybridization was conducted to identify each chromosome at metaphase I. The new Col and Ler tetraploids showed high multivalent frequencies, exceeding the theoretical 66.66% expected on a simple random end-pairing model, thus indicating that there are more than two autonomous synaptic sites per chromosome despite their small size. However, a significant excess of bivalent pairs was found in the Col/Ler hybrid, mainly due to the contribution of chromosomes 2 and 3. The mean chiasma frequencies of the three artificial autotetraploids were about twofold the corresponding mean cell chiasma frequencies of their diploid counterparts. The relative contribution of each chromosome to the total chiasma frequency was similar in the three genotypes, with the exception of a lower contribution of chromosome 3 in the hybrid. Preferences for chiasma formation between identical and homologous chromosomes were analyzed in Col/Ler 4x, taking advantage of the cytological differences between the accessions: variations in the size of the 45S rDNA region on the short arm of chromosome 2 and changes in the size and localization of the 5S rDNA region in chromosome 3. We observed a different behavior of chromosomes 2 and 3, i.e., random chiasma formation between identical and homologous chromosomes 2, and preferences for chiasma formation between homologous chromosomes 3. Hence, our results reveal the existence of chromosome-specific mechanisms responsible for these preferences.

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Section: Introductionmentioning

confidence: 99%

Competition for Chiasma Formation Between Identical and Homologous (But Not Identical) Chromosomes in Synthetic Autotetraploids of Arabidopsis thaliana

2019

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“…This allowed pairing analysis, the results of which are presented in Table 1 The preferential pairing of identical Ks might be explained by their closer proximity and therefore higher pairing affinity among identical chromosomes, as suggested by Benavente & Orellana (1989). In A. lucidus the doubling of the Ks resulted from the last unequal gonial mitosis.…”

Section: Resultsmentioning

confidence: 99%

Preferential pairing in the germ line limited chromosomes of Acricotopus lucidus (Diptera, Chironomidae)

Staiber

1991

Heredity

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“…As metaphase I rye bivalents are not easily identified by standard staining techniques, a Giemsa C-banding procedure (Giráldez & Orellana, 1979) was used to identify bivalents and bivalent arms at metaphase I. This technique has been extensively used to identify unambiguously rye bivalent arms in meiosis of rye and triticale (Fominaya & Orellana, 1988;Benavente & Orellana, 1989).…”

Section: Methodsmentioning

confidence: 99%

A possible effect of B-chromosomes on metaphase I homologous chromosome association in rye

1991

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The metaphase I association of rye chromosomes was examined both in normal plants (2n = 14) and in plants with rye B chromosomes (2n = 14+ Bs) using the C-banding technique. It was found that B chromosomes (Bs) affect homologous chromosome association. B isochromosomes (iso-Bs) were present in several plants; their presence was deduced, in addition to the morphology of chromosomes at mitosis, from the meiotic association between the two arms of the B and it was confirmed by its C-banding pattern. The strongest increase in rye metaphase association (measured as bound arms) was produced by the presence of the iso-B short (iso-BS) chromosome. The comparison of chromosome association between plants with and without Bs seems to point to the existence of a promoting effect on meiotic chromosome association by Bs, and in particular by the short arm.

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Pairing competition between metacentric and telocentric chromosomes in autotetraploid rye

Cited by 8 publications

References 20 publications

Competition for Chiasma Formation Between Identical and Homologous (But Not Identical) Chromosomes in Synthetic Autotetraploids of Arabidopsis thaliana

Competition for Chiasma Formation Between Identical and Homologous (But Not Identical) Chromosomes in Synthetic Autotetraploids of Arabidopsis thaliana

Preferential pairing in the germ line limited chromosomes of Acricotopus lucidus (Diptera, Chironomidae)

A possible effect of B-chromosomes on metaphase I homologous chromosome association in rye

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