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Gametogenesis and nucleotypic effects in the tetraploid red vizcacha rat, Tympanoctomys barrerae (Rodentia, Octodontidae)

Author
GALLARDO,MILTON H

GARRIDO,ORLANDO

BAHAMONDE,RAÚL

GONZÁLEZ,MARCELO

Full text
https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0716-97602004000500006
Abstract
Nucleotypic effects link DNA content with nuclear size and cell dimensions of reproductive cells in polyploid organisms. We studied the gametogenesis of the allotetraploid rodent Tympanoctomys barrerae, aiming to determine these effects in reproductive cells. The species' cofamily members, Octodon degus and Spalacopus cyanus were used as control. Spermatogenesis and oogenesis in T. barrerae follows the pattern of differentiation and sequence of events of the control species, but varied nucleotypic effects were observed. Exceedingly large, spatulated spermatozoa with a submedially attached flagellum are characteristic of male T. barrerae. The diameter of the nuclei of primordial and growing follicles as well as those of the Graaff follicles, of the granulose, and of luteal cells are significantly larger and heavily heterochromatic. Moreover, the width of the pellucid zone is 108% thicker in T. barrerae than in S. cyanus. Binucleation was recorded in 26% of luteal bodies examined whereas no binucleated cells are detected in the diploid control. Likewise, large heterochromatic nucleoli were observed in the follicle cells but not in S. cyanus. This finding and the high heterochromatin content of reproductive cells in the red vizcacha rat is probably associated with its genome complexity so that redundant genetic information is silenced through heterochromatinization
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Artes, Arquitectura y UrbanismoCiencias Agrarias, Forestales y VeterinariasCiencias Exactas y NaturalesCiencias SocialesDerechoEconomía y AdministraciónFilosofía y HumanidadesIngenieríaMedicinaMultidisciplinarias
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Universidad de ChileUniversidad Católica de ChileUniversidad de Santiago de ChileUniversidad de ConcepciónUniversidad Austral de ChileUniversidad Católica de ValparaísoUniversidad del Bio BioUniversidad de ValparaísoUniversidad Católica del Nortemore

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