Identical Linear Order of Chromosomes in Both Gametes of the Acoel Turbellarian
            <i>Polychoerus carmelensis:</i>
            A Preliminary Note

Costello, Donald P.

doi:10.1073/pnas.67.4.1951

Cited by 39 publications

(17 citation statements)

References 19 publications

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“…(2) The spatial organization could be newly produced in each generation if the chromosomes carry (genetical) information allowing them to become oriented in the newly constituted zygote. The observations of Costello (1970) lend indirect support to the first hypothesis. Costello found that the ordered arrangement of chromosomes in the first cleavage division of the flatworm Polychoerus carmelinis could be accounted for in terms of two identical linear arrangements of chromosomes with only minor permutations of order in one.…”

Section: The Origin Of Spatial Organizationsupporting

confidence: 58%

Hybrid Dysgenesis in Drosophila Melanogaster: A Possible Explanation in Terms of Spatial Organization of Chromosomes

Ja¹

1976

Aust. Jnl. Of Bio. Sci.

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Male.recombination and female sterility, two aspects of hybrid dysgenesis in D. melanogaster, have been studied in crosses between a locally collected wild population and laboratory strains. Dysgenesis occurs in the Fl hybrid of such crosses only if the wild type is used as maie parent and the laboratory strain as female, suggesting an interaction between genotype and cytoplasm. However the results from further crosses are difficult to interpret in terms of a conventional genotype--cytoplasm model, and suggest that for dysgenesis to occur it is necessary-that the wild-type chromosomes be contributed by the male parent. Furthermore, receipt of any of the three major wild-type chromosomes in crosses to laboratory females is sufficient to cause hybrid dysgenesis.A model in terms of spatial organization of chromosomes is put forward to explain these results. It is postulated that (1) normal nuclear functioning requires a definite spatial organiZation of chromosomes, which is presumably achieved by chromosome-membrane associations, (2) chromosomes are inherited from the female parent with spatial ordering preserved, i.e. membranes and associated chromosomes are handed on directly from the female parent, (3) spatial ordering is not necessarily preserved in male gametes, and paternally derived chromosomes carry information enabling them to become correctly organized within the zygote nucleus, and (4) hybrid dysgenesis results when the chromosome(s) from the male of one strain lack the information to become correctly organized in the nucleus of a second strain. The model seems to explain all aspects of the results, and offers the possibility that the present system may yield information on the genetics of membrane development and other aspects of spatial organization in the normal nucleus.

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Section: The Origin Of Spatial Organizationsupporting

confidence: 58%

Hybrid Dysgenesis in Drosophila Melanogaster: A Possible Explanation in Terms of Spatial Organization of Chromosomes

Ja¹

1976

Aust. Jnl. Of Bio. Sci.

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“…The chromosomes of the two genomes occur in blocks (Costello, 1970). Careful examination of this singular metaphase plate shows not only that the order of chromosomes within each genome is the same, but that the arms of adjacent chromosomes are roughly the same lengths.…”

Section: Proposed Model Of Interphase Chromosome Arrangementmentioning

confidence: 99%

Interphase chromosome order: A proposal

Pussell

1984

Genetica

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A model for the arrangement of chromosomes in interphase nuclei is proposed. The model assumes that interphase chromosomes have a Rabl orientation (a relic telophase arrangement). During interphase and prophase telomeres are attached to the nuclear envelope often in pairs. The association of telomeres, homologous or nonhomologous, is based on similarity of arm lengths and occurs at the time the nuclear envelope reforms. At this stage arm lengths will vary to some extent due to the amount of uncoiling etc. The sequence of chromosomes resulting from telomere-telomere pairing may vary among cells, but the number of arrangements will be restricted by arm length similarities.The ramifications of this model on meiotic pairing, the constant attachment of chromosomes to some structure throughout the cell cycle, the distribution of genes within nuclei, and chromosome evolution are raised.

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“…Another interesting evidence showing that chromosomes have fixed location was the visualization of homologue chromosomes positioned in opposite halves of the metaphase plate. This aspect observed in early embryogenesis of a turbellarian (Costello 1970) indicated the occurrence of an ordered chromosome transmission from gametes to 286 MARIA LUIZA BEÇAK, WILLY BEÇAK and ALEXANDRE PEREIRA following generations. Non-random chromosome distribution and somatic pairing were also evidenced in uncultured cells from Chinese hamster (Juricek 1975).…”

Section: Introductionmentioning

confidence: 99%

Somatic pairing, endomitosis and chromosome aberrations in snakes (Viperidae and Colubridae)

Beçak

Pereira

2003

An. Acad. Bras. Ciênc.

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The positioning of macrochromosomes of Bothrops jararaca and Bothrops insularis (Viperidae) was studied in undistorted radial metaphases of uncultured cells (spermatogonia and oogonia) not subjected to spindle inhibitors. Colchicinized metaphases from uncultured (spleen and intestine) and cultured tissues (blood) were also analyzed. We report two antagonic non-random chromosome arrangements in untreated premeiotic cells: the parallel configuration with homologue chromosomes associated side by side in the metaphase plate and the antiparallel configuration having homologue chromosomes with antipolar distribution in the metaphase ring. The antiparallel aspect also appeared in colchicinized cells. The spatial chromosome arrangement in both configurations is groupal size-dependent and maintained through meiosis. We also describe, in untreated gonia cells, endomitosis followed by reductional mitosis which restores the diploid number. In B. jararaca males we observed that some gonad regions present changes in the meiotic mechanism. In this case, endoreduplicated cells segregate the diplochromosomes to opposite poles forming directly endoreduplicated second metaphases of meiosis with the suppression of first meiosis. By a successive division, these cells form nuclei with one set of chromosomes. Chromosome doubling in oogonia is known in hybrid species and in parthenogenetic salamanders and lizards. This species also presented chromosome rearrangements leading to aneuploidies in mitosis and meiosis. It is suggested that somatic pairing, endomitosis, meiotic alterations, and chromosomal aberrations can be correlated processes. Similar aspects of nuclei configurations, endomitosis and reductional mitosis were found in other Viperidae and Colubridae species.

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Identical Linear Order of Chromosomes in Both Gametes of the Acoel Turbellarian Polychoerus carmelensis: A Preliminary Note

Cited by 39 publications

References 19 publications

Hybrid Dysgenesis in Drosophila Melanogaster: A Possible Explanation in Terms of Spatial Organization of Chromosomes

Hybrid Dysgenesis in Drosophila Melanogaster: A Possible Explanation in Terms of Spatial Organization of Chromosomes

Interphase chromosome order: A proposal

Somatic pairing, endomitosis and chromosome aberrations in snakes (Viperidae and Colubridae)

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