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On the origin of crossover interference : a chromosome oscillatory movement (COM) model
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Hultén, Maj A. (2011) On the origin of crossover interference : a chromosome oscillatory movement (COM) model. Molecular Cytogenetics, Vol.4 (No.10). doi:10.1186/1755-8166-4-10 ISSN 1755-8166.
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Official URL: http://dx.doi.org/10.1186/1755-8166-4-10
Abstract
Background: It 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.
Results: The 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.
Conclusions: The 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.
Item Type: | Journal Article | ||||
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Subjects: | Q Science > QH Natural history > QH426 Genetics | ||||
Divisions: | Faculty of Science, Engineering and Medicine > Medicine > Warwick Medical School | ||||
Library of Congress Subject Headings (LCSH): | Crossing over (Genetics) | ||||
Journal or Publication Title: | Molecular Cytogenetics | ||||
Publisher: | BioMed Central Ltd. | ||||
ISSN: | 1755-8166 | ||||
Official Date: | 8 April 2011 | ||||
Dates: |
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Volume: | Vol.4 | ||||
Number: | No.10 | ||||
DOI: | 10.1186/1755-8166-4-10 | ||||
Status: | Peer Reviewed | ||||
Access rights to Published version: | Open Access (Creative Commons) | ||||
Date of first compliant deposit: | 16 December 2015 | ||||
Date of first compliant Open Access: | 16 December 2015 |
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