Chromosomal distribution of the major satellite DNA of South American rodents of the genus &lt;i&gt;Ctenomys&lt;/i&gt;

Rossi, María Susana; Redi, Carlo Alberto; Viale, Giulia; Massarini, Alicia; Capanna, Ernesto

doi:10.1159/000133956

Cited by 28 publications

(31 citation statements)

References 17 publications

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“…Thus, the P. g. guaire-P. trinitatis transition can be regarded as one of those cases (Mus, Reithrodontomys, Microtus as well as Ctenomys, for the last two species see Modi. 1993 andRossi et al, 1995) in which structural rear rangements within the genome have been accompanied by a con certed change in the rep DNA chromosome allocation and amplification within a relatively short period.…”

Section: Discussionmentioning

confidence: 99%

Genome composition in Venezuelan spiny-rats of the genus Proechimys (Rodentia, Echimyidae). I. Genome size, C-heterochromatin and repetitive DNAs in situ hybridization patterns

Garagna

Pérez-Zapata²,

Zuccotti

et al. 1997

Cytogenet Genome Res

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The genome sizes of the Venezuelan spiny-rats Proechimys guairae guairae (2n = 48) and P. trinitatis (2n = 62) were evaluated and proved to be 12.5 ± 0.5pg and 12.6 ± 0.3pg respectively, the highest so far recorded among mammals; also the C-heterochromatin (32.7 %, Coefficient of Variation [CV] 3.8 and 35.8%, CV4.4) and GC (44.2%, CV2.7 and 43.6%, CV 2.9) contents are very high. Highly repetitive (rep) DNAs were isolated from restriction enzyme digested genomic DNAs of both species. The intra- and inter-specific chromosomal allocations of these rep DNAs were analyzed by direct and cross-hybridizations. Results show that the two genomes harbour several rep DNA families which show both species-specificity and interspecific relatedness in their in situ hybridization patterns. The rep DNA families show an equilocal distribution at both the pericentromeric areas of all chromosomes and in the whole arms of two pairs of the uniarmed group, suggesting co-evolution of the rep DNAs. P. g. guairae BamHI digested DNA, when cloned and sequenced, proved to consist of a long “composite” unit (1,239 bp) containing two copies of each of 75-bp and 110-bp internal subrepeats. Karyotype restructuring between P. g. guairae and P. trinitatis, mainly due to Robertsonian changes, was accompanied by slight intra- and intergenomic movements of the putative satellite DNA families within stable genome sizes and C-heterochromatin contents. We discuss the findings obtained in Proechimys in the light of those regarding the kangaroo rat, the pocket gopher and the house mouse; they support the idea that karyotype restructuring could be the expression of molecular driven events of rep DNA amplification and homogenisation through non-homologous chromosomes.

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Section: Discussionmentioning

confidence: 99%

Genome composition in Venezuelan spiny-rats of the genus Proechimys (Rodentia, Echimyidae). I. Genome size, C-heterochromatin and repetitive DNAs in situ hybridization patterns

Garagna

Pérez-Zapata²,

Zuccotti

et al. 1997

Cytogenet Genome Res

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“…Chromosomal differentiation in this genus also includes a high degree of variation in the amount and localization of heterochromatin, ranging from positive C-bands in the centromeric area of few chromosomes, to karyotypes showing heterochromatic short arms in the whole chromosomes (Rossi et al 1995;Novello et al 1996). These patterns were confirmed in Uruguayan populations.…”

Section: Introductionmentioning

confidence: 71%

G-banding patterns of the genusCtenomysfrom Uruguay (Rodentia Ctenomydae): high karyotype variation but chromosome arm conservation

2014

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The genus Ctenomys present a wide 2n and fundamental number (FN) variation in Uruguay and throughout their distribution across the south of the Neotropical region. In this study we analyze chromosome variation of this genus in Uruguay using G and C bands. G-band comparison makes clear that this chromosome variation is reduced if we take into account entire chromosomes and chromosome arms homologies. This could be explained as an adaptation to chromosome variation (2n and FN) without changing gene order or linkage groups. On the other hand, C-banding showed a high variability in amount and localization in the karyotypes analyzed here. These differences could be due to differential amplification of the repetitive DNA (RPSC) characteristic of this genus. Nevertheless, other mechanisms could be involved as repetitive DNA interchange at the chromocenters in the meiosis pachytene, where non homologous chromosomes meet. In this scenario, chromosome rearrangements such as Robertsonian translocations and whole chromosome conservation are of particular interest since these provide a way to conserve gene order. Why Ctenomys chromosomes are prone to rearrangements is not clear, albeit several mammal species present a similar picture. This kind of chromosome change could be involved in the maintenance of chromosome order at the nuclear level. In this paper, we present evidence showing that chromosome and genetic changes are not unavoidably related in Ctenomys, which questions the hypothesis about speciation based on chromosomal changes.

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“…Much discussion has been devoted to the reasons for such explosive diversification, and arguments have focused on population structure (Reig 1970), chromosomal multiformity (Reig and Kiblisky 1969, Reig 1989) and features of the genome that may have facilitated the latter (Rossi et al 1995). We used an array of tests based on phylogenies to test for rapid diversification and unusually high divergence in tuco-tucos and, when possible, other subterranean taxa.…”

Section: Discussionmentioning

confidence: 99%

ARE RATES OF DIVERSIFICATION IN SUBTERRANEAN SOUTH AMERICAN TUCO-TUCOS (GENUSCTENOMYS, RODENTIA: OCTODONTIDAE) UNUSUALLY HIGH?

Cook

Lessa

1998

Evolution

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Abstract.-Subterranean rodents have been used frequently as examples of explosive speciation in mammals. We tested for differential rates of diversification by using information from molecular phylogenies to focus primarily on tuco-tucos (Rodentia: Octodontidae), the most speciose lineage of subterranean rodents. Tuco-tucos were not significantly more diverse than their sister taxon (octodontines); however, a lineages-through-time analysis suggests an increase in diversification at the base of the tuco-tuco clade.

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Chromosomal distribution of the major satellite DNA of South American rodents of the genus <i>Ctenomys</i>

Cited by 28 publications

References 17 publications

Genome composition in Venezuelan spiny-rats of the genus <i>Proechimy</i><i>s</i> (Rodentia, Echimyidae). I. Genome size, C-heterochromatin and repetitive DNAs in situ hybridization patterns

Genome composition in Venezuelan spiny-rats of the genus <i>Proechimy</i><i>s</i> (Rodentia, Echimyidae). I. Genome size, C-heterochromatin and repetitive DNAs in situ hybridization patterns

G-banding patterns of the genusCtenomysfrom Uruguay (Rodentia Ctenomydae): high karyotype variation but chromosome arm conservation

ARE RATES OF DIVERSIFICATION IN SUBTERRANEAN SOUTH AMERICAN TUCO-TUCOS (GENUSCTENOMYS, RODENTIA: OCTODONTIDAE) UNUSUALLY HIGH?

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