Wyniki wyszukiwania

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B chromosome system in populations of Oryzomys flavescens (Rodentia, Cricetidae) from southern Brazil

100%

Sbalqueiro I. J., Mattevi M. S., Oliveira L. F. B., Solano M. J. V.

Acta Theriologica

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1991

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tom 36

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nr 1-2

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Chromosomal description of the rodent genera Oecomys and Nectomys from Brazil

100%

Andrades-Miranda J., Oliveira L. F. B., Zanchin N. I. T., Mattevi M. S.

Acta Theriologica

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2001

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tom 46

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nr 3

We analysed karyotypes of five taxa of the rodent genera Oecomys and Nectomys, trapped in 14 localities in an area ranging from 8° to 29°S on Brazilian territory. Oecomys cf. concolor, collected in the Amazon and in two localities of the Cerrado biome, showed a 2n = 60 karyotype constituted by a pair of large subtelocentric chromosomes, a small metacentric pair and 27 acrocentric pairs. The X chromosome was a large submetacentric and a subtelo-submetacentric, the morphology of the latter showing variable C-banding patterns. In all three localities the Y chromosome was a medium size heterochromatic acrocentric. Two individuals from the Cerrado had a heterochromatic acrocentric B-chromosome. Oecomys cf. bicolor presented two cytotypes, 2n = 80 in the specimens from the Cerrado biome and 2n = 82 in individuals trapped in the Amazon. The 2n = 80 cytotype 1 showed a large subtelocentric, 22 biarmed pairs (medium to small) and 16 acrocentric autosomal pairs. The karyotype of the 2n = 82 cytotype 2 is constituted by 15 biarmed chromosomes (median to small) and 25 acrocentric pairs with heterochromatic blocks at pericentromeric regions. The sexual pairs were the same (large submetacentric X and median acrocentric Y) in both cytotypes. In O. cf. concolor and in both cytotypes of O. cf. bicolor the nucleolar organizer regions were observed in 1-3 pairs, located in the short arms. Nectomys genus presented two cytotypes, 2n = 52-55 (N. rattus, with 0-3 biarmed heterochromatic accessory chromosomes) and 2n = 56-59 (N. squamipes, bearing 0-3 biarmed, hetero- chromatic, B-chromosomes). These 2 cytotypes occupy disjunct regions of South America, with overlapping areas in the Brazilian states of Pernambuco, Bahia, and Mato Grosso do Sul.

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Karyotype and species diversity of the genus Delomys (Rodentia, Cricetidae) in Brazil

76%

Zanchin N. I. T., Sbalqueiro I. J., Langguth A., Bossle R. C., Castro E. C., Oliveira L. F. B., Mattevi M. S.

Acta Theriologica

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1992

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tom 37

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nr 1-2

Cytogenetic analyses were performed in 39 specimens of Delomys trapped in six localities distributed along the Atlantic forest range of the genus. Only two karyotypic forms were found: 2n = 72, FN = 90 to the north and 2n = 82, FN = 80 to the south, with an overlapping area in São Paulo and Paraná states. No hybrids were found and given the large difference in karyotype it is likely that any hybrids produced would be infertile. Based on the skin coloration and type localities of the species described it is suggested that the 2n = 72 taxon corresponds to Delomys sublineatus and the 2n = 82 form to D. dorsalis.

Ograniczanie wyników

3 Acta Theriologica

3 Mattevi M. S.

3 Oliveira L. F. B.

2 Sbalqueiro I. J.

2 Zanchin N. I. T.

1 Andrades-Miranda J.

1 Bossle R. C.

1 Castro E. C.

1 Langguth A.

1 Solano M. J. V.

1 2001

1 1992

1 1991

B chromosome system in populations of Oryzomys flavescens (Rodentia, Cricetidae) from southern Brazil

Chromosomal description of the rodent genera Oecomys and Nectomys from Brazil

Karyotype and species diversity of the genus Delomys (Rodentia, Cricetidae) in Brazil