Gametogenesis and nucleotypic effects in the tetraploid red vizcacha rat, Tympanoctomys barrerae (Rodentia, Octodontidae)
Biol. Res
;
37(4,supl.A): 765-775, 2004. ilus, tab
Article
in English
| LILACS
| ID: lil-399656
RESUMO
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 percent thicker in T. barrerae than in S. cyanus. Binucleation was recorded in 26 percent 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.
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Rodentia
/
Cell Nucleus
Limits:
Animals
Language:
English
Journal:
Biol. Res
Journal subject:
Biology
Year:
2004
Type:
Article
/
Project document
Affiliation country:
Chile
Institution/Affiliation country:
Instituto de Ecología y Evolución/CL
/
Universidad Austral de Chile/CL
Similar
MEDLINE
...
LILACS
LIS