Hexavalents in spermatocytes of Robertsonian heterozygotes between Mus m. domesticus 2n-26 from the Vulcano and Lipari Islands (Aeolian Archipelago, Italy)
Author
dc.contributor.author
Berríos del Solar, María Soledad
Author
dc.contributor.author
Fernández Donoso, Raúl
Author
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Page, Jesús
Author
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Ayarza Ramírez, Gladys
Author
dc.contributor.author
Capanna, Ernesto
Author
dc.contributor.author
Solano, Emanuela
Author
dc.contributor.author
Castiglia, Riccardo
Admission date
dc.date.accessioned
2018-07-20T14:00:42Z
Available date
dc.date.available
2018-07-20T14:00:42Z
Publication date
dc.date.issued
2018
Cita de ítem
dc.identifier.citation
European Journal of Histochemistry 2018; volume 62: 2894
es_ES
Identifier
dc.identifier.other
10.4081/ejh.2018.2894
Identifier
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https://repositorio.uchile.cl/handle/2250/150083
Abstract
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The size and shape of the chromosomes, as well as the chromosomal domains that compose them, are determinants in the distribution and interaction between the bivalents within the nucleus of spermatocytes in prophase I of meiosis. Thus the nuclear architecture characteristic of the karyotype of a species can be modified by chromosomal changes such as Robertsonian (RB) chromosomes. In this study we analysed the meiotic prophase nuclear organization of the heterozygous spermatocytes from Mus musculus domesticus 2n=26, and the synaptic configuration of the hexavalent formed by the dependent Rb chromosomes Rbs 6.16, 16.10, 10.15, 15.17 and the telocentric chromosomes 6 and 17. Spreads of 88 pachytene spermatocytes from two males were studied and in all of them five metacentric bivalents, four telocentric bivalents, one hexavalent and the XY bivalent were observed. About 48% of the hexavalents formed a chain or a ring of synapsed chromosomes, the latter closed by synapsis between the short arms of telocentric chromosomes 6 and 17. About 52% of hexavalents formed an open chain of 10 synapsed chromosomal arms belonging to 6 chromosomes. In about half of the unsynapsed hexavalents one of the telocentric chromosome short arms appears associated with the X chromosome single axis, which was otherwise normally paired with the Y chromosome. The cluster of pericentromeric heterochromatin mostly determines the hexavalent's nuclear configuration, dragging the centromeric regions and all the chromosomes towards the nuclear envelope similar to an association of five telocentric bivalents. These reiterated encounters between these chromosomes restrict the interactions with other chromosomal domains and might favour eventual rearrangements within the metacentric, telocentric or hexavalent chromosome subsets. The unsynapsed short arms of telocentric chromosomes frequently bound to the single axis of the X chromosome could further complicate the already complex segregation of hexavalent chromosomes.
es_ES
Patrocinador
dc.description.sponsorship
VID Universidad de Chile (Chile)
Ministerio de Economia y Competitividad (Spain)
CGL2014-53106-P
Hexavalents in spermatocytes of Robertsonian heterozygotes between Mus m. domesticus 2n-26 from the Vulcano and Lipari Islands (Aeolian Archipelago, Italy)