Proximal Chiasma Localization within an Interstitial Chromosome Segment, a Likely Correlate of Adjacent-2 Segregation of Translocation Causing Multivalents in the Mouse

Boer, P. de

doi:10.2307/3429151

Cited by 4 publications

(5 citation statements)

References 2 publications

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“…In stark contrast to the normal situation in non-acrocentric chromosomes there is then a tendency for chiasmata to occupy positions near to/adjacent to the centromere, as well as a substantial reduction in the crossover/interference distance over the centromere. A similar tendency for an increased frequency of chiasmata within the interstitial segment has been seen in reciprocal translocations in mice [76,77]. …”

Section: Resultssupporting

confidence: 69%

On the origin of crossover interference: A chromosome oscillatory movement (COM) model

Hultén

2011

Mol Cytogenet

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BackgroundIt is now nearly a century since it was first discovered that crossovers between homologous parental chromosomes, originating at the Prophase stage of Meiosis I, are not randomly placed. In fact, the number and distribution of crossovers are strictly regulated with crossovers/chiasmata formed in optimal positions along the length of individual chromosomes, facilitating regular chromosome segregation at the first meiotic division. In spite of much research addressing this question, the underlying mechanism(s) for the phenomenon called crossover/chiasma interference is/are still unknown; and this constitutes an outstanding biological enigma.ResultsThe Chromosome Oscillatory Movement (COM) model for crossover/chiasma interference implies that, during Prophase of Meiosis I, oscillatory movements of the telomeres (attached to the nuclear membrane) and the kinetochores (within the centromeres) create waves along the length of chromosome pairs (bivalents) so that crossing-over and chiasma formation is facilitated by the proximity of parental homologs induced at the nodal regions of the waves thus created. This model adequately explains the salient features of crossover/chiasma interference, where (1) there is normally at least one crossover/chiasma per bivalent, (2) the number is correlated to bivalent length, (3) the positions are dependent on the number per bivalent, (4) interference distances are on average longer over the centromere than along chromosome arms, and (5) there are significant changes in carriers of structural chromosome rearrangements.ConclusionsThe crossover/chiasma frequency distribution in humans and mice with normal karyotypes as well as in carriers of structural chromosome rearrangements are those expected on the COM model. Further studies are underway to analyze mechanical/mathematical aspects of this model for the origin of crossover/chiasma interference, using string replicas of the homologous chromosomes at the Prophase stage of Meiosis I. The parameters to vary in this type of experiment will include: (1) the mitotic karyotype, i.e. ranked length and centromere index of the chromosomes involved, (2) the specific bivalent/multivalent length and flexibility, dependent on the way this structure is positioned within the nucleus and the size of the respective meiocyte nuclei, (3) the frequency characteristics of the oscillatory movements at respectively the telomeres and the kinetochores.

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Section: Resultssupporting

confidence: 69%

On the origin of crossover interference: A chromosome oscillatory movement (COM) model

Hultén

2011

Mol Cytogenet

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“…As a consequence, there is a correlated rise in the rate of zygotic and fetal loss during gestation. A number of factors have been suggested to influence the meiotic segregation of translocated chromosomes and thus the rate of production of genetically unbalanced gametes: the positions of the breakpoints; the number and distribution of chiasmata in the multivalent configuration; and genetic background (see de Boer 1979, Jalbert et al 1980, Rickards 1983, Sybenga & Rickards 1987. Similar deleterious effects on embryonic viability and congenital malformations have been described in the laboratory mouse (Kirk & Searle 1988).…”

Section: Introductionmentioning

confidence: 83%

“…Oshimura & Takagi 1975;de Boer 1976de Boer , 1979. The rate of non-disjunction has been reported to increase by a similar magnitude in male mice heterozygous for other reciprocal translocations (e.g.…”

Section: C-bandingmentioning

confidence: 92%

“…In humans, for example, it has been estimated that reciprocal translocations are responsible for 2% of spontaneous abortions and approximately 0.06% of abnormal livebirths (Jacobs 1990). Predictive models of meiotic chromosome behaviour have been based on characteristics such as translocation breakpoints, and thus the relative lengths of translocated and untranslocated chromosomal segments (Jalbert et al 1980) and chiasma distribution (de Boer 1979). A number of factors have been suggested to influence the meiotic segregation of translocated chromosomes and thus the rate of production of genetically unbalanced gametes: the positions of the breakpoints; the number and distribution of chiasmata in the multivalent configuration; and genetic background (see de Boer 1979, Jalbert et al 1980, Rickards 1983, Sybenga & Rickards 1987.…”

Section: Introductionmentioning

confidence: 99%

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Analysis using dual-colour fluorescencein situ hybridization of meiotic chromosome segregation in male mice heterozygous for a reciprocal translocation

Tease¹

1996

Chromosome Res

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Meiotic chromosome behaviour was investigated in male mice heterozygous for the translocation T(7;16)67H. At metaphase I, chain-of-four quadrivalents were present in approximately 80% of the spermatocytes; the bulk of remaining cells contained a ring quadrivalent, with only a few having either a trivalent plus univalent configuration or two bivalents. A low rate of non-disjunction, approximately 5%, was found through analysis of C-banded metaphase II spermatocytes. Using fluorescence in situ hybridization with differentially labelled whole chromosome paints, a wide array of segregation products were observed at metaphase II, depending on whether they arose from alternate, adjacent I, adjacent II orientation at metaphase I or were uninformative for alternative/adjacent I because of the presence of a chiasma in an interstitial pairing segment. Some 62% of the cells fell into this latter category, with only small proportions clearly arising through alternate (1.8%) or adjacent I (0.7%) orientations. Approximately 30% of the cells contained the products of adjacent II orientation. Consideration of the data suggested that most of these cells arose from metaphase I cells that contained a chain quadrivalent. Ring quadrivalents appeared predominantly to orientate in an alternate/adjacent I manner.

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“…For both species the deleterious effects on embryonic viability result from the increased production of genetically imbalanced gametes by RT carriers. The elevated genetic risk is known to vary between different RTs, however, and a number of factors have been suggested as potential influences on their meiotic behaviour: the size of the translocated segments; the length of the interstitial regions; chiasma frequencies and distributions; sex; and, genetic background (see de Boer 1979;Jalbert et al 1980;de Boer et al 1983;Rickards 1983;Sybenga and Rickards 1987;Pellestor et al 1997). Until recently, these factors have been difficult to investigate in a systematic fashion, largely because of limitations imposed by classical cytogenetic approaches.…”

Section: Introductionmentioning

confidence: 98%

Chiasma distributions and chromosome segregation in male and female translocation heterozygous mice analysed using FISH

Tease

1998

Chromosoma

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Two factors postulated to influence the meiotic behaviour of reciprocal translocations were investigated. Firstly, variation in the length of translocated and non-translocated segments was studied in male mice using four different rearrangements involving chromosomes 2 and 4. Secondly, sex-related effects were analysed through comparison of the meiotic behaviour of two translocations in male and female germ cells. In the first part of the study, primary and secondary spermatocytes of male mice carrying a translocation [T(2;4)1Ca, T(2;4)13H, T(2;4)1Sn, or T(2;4)1Go] were screened. Each rearrangement had different proportions of cells with ring and chain quadrivalents at metaphase I; the T(2;4)1Sn heterozygote also had a high rate (45%) of translocation bivalents. In general, the translocations had elevated chiasma frequencies in the rearranged chromosomes compared with structurally normal chromosomes 2 and 4, although the extent of the effect varied. Each rearrangement produced a different array of segregation products at metaphase II, reflecting their contrasting frequencies of multivalent configurations at metaphase I. Comparison of chromosome behaviour at metaphase I and II suggested that certain configurations tended to adopt particular orientations. However, it was also clear that such correlations were imprecise and that other factors, possibly the exact positions of chiasmata, also played a role in multivalent orientation. Two rearrangements, T(2;4)1Go and T(7;16)67H, were analysed in female mice. The frequencies of the various multivalent types at metaphase I differed from those in male carriers of these rearrangements owing to an increased chiasma frequency in oocytes in some of the pairing segments. Not surprisingly, the segregation products seen in metaphase II cells showed some differences from the pattern recorded in male germ cells. For T(2;4)1Go, the sex-related difference in segregation patterns resulted in a diminished expectation of genetically imbalanced gametes, although this was not the case for T(7;16)67H.

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Proximal Chiasma Localization within an Interstitial Chromosome Segment, a Likely Correlate of Adjacent-2 Segregation of Translocation Causing Multivalents in the Mouse

Cited by 4 publications

References 2 publications

On the origin of crossover interference: A chromosome oscillatory movement (COM) model

On the origin of crossover interference: A chromosome oscillatory movement (COM) model

Analysis using dual-colour fluorescencein situ hybridization of meiotic chromosome segregation in male mice heterozygous for a reciprocal translocation

Chiasma distributions and chromosome segregation in male and female translocation heterozygous mice analysed using FISH

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