ARE RATES OF DIVERSIFICATION IN SUBTERRANEAN SOUTH AMERICAN TUCO-TUCOS (GENUS<i>CTENOMYS</i>, RODENTIA: OCTODONTIDAE) UNUSUALLY HIGH?

Cook, Joseph A.; Lessa, Enrique P.

doi:10.1111/j.1558-5646.1998.tb02035.x

Cited by 30 publications

(14 citation statements)

References 44 publications

(68 reference statements)

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“…ROBO, C. goodfellowi, and C. boliviensis is not strongly supported (figs. 1 and 2), previous studies (Cook and Yates 1994;Cook and Lessa 1998) indicate that these species are related. Ctenomys steinbachi is thought to have undergone rapid and extensive chromosomal evolution from karyotypes of higher diploid numbers .…”

Section: Evolution Of Rpcs Copy Number and Chromosomes In Tuco-tucosmentioning

confidence: 81%

Recurrent Amplifications and Deletions of Satellite DNA Accompanied Chromosomal Diversification in South American Tuco-tucos (Genus Ctenomys, Rodentia: Octodontidae): A Phylogenetic Approach

Slamovits

Cook²,

Lessa³

et al. 2001

Molecular Biology and Evolution

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We investigated the relationship between satellite copy number and chromosomal evolution in tuco-tucos (genus Ctenomys), a karyotypically diverse clade of rodents. To explore phylogenetic relationships among 23 species and 5 undescribed forms, we sequenced the complete mitochondrial cytochrome b genes of 27 specimens and incorporated 27 previously published sequences. We then used quantitative dot-blot techniques to assess changes in the copy number of the major Ctenomys satellite DNA (satDNA), named RPCS. Our analysis of the relationship between variation in copy number of RPCS and chromosomal changes employed a maximum-likelihood approach to infer the copy number of the satellite RPCS in the ancestors of each clade. We found that amplifications and deletions of RPCS were associated with extensive chromosomal rearrangements even among closely related species. In contrast, RPCS copy number stability was observed within clades characterized by chromosomal stability. This example reinforces the suspected role of amplification, deletion, and intragenomic movement of satDNA in promoting extensive chromosomal evolution.

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Section: Evolution Of Rpcs Copy Number and Chromosomes In Tuco-tucosmentioning

confidence: 81%

Recurrent Amplifications and Deletions of Satellite DNA Accompanied Chromosomal Diversification in South American Tuco-tucos (Genus Ctenomys, Rodentia: Octodontidae): A Phylogenetic Approach

Slamovits

Cook²,

Lessa³

et al. 2001

Molecular Biology and Evolution

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110

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“…The genus Ctenomys (Caviomorpha: Ctenomyidae), commonly known as tuco-tucos comprises more than 50 species occupying much of South America [7]. Besides one species that is known to be social [8], [9], most of them are solitary and emerge aboveground on a daily basis for foraging, therefore exposing themselves to surface Ta [10]–[12].…”

Section: Introductionmentioning

confidence: 99%

Rhythmic 24 h Variation of Core Body Temperature and Locomotor Activity in a Subterranean Rodent (Ctenomys aff. knighti), the Tuco-Tuco

et al. 2014

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The tuco-tuco Ctenomys aff. knighti is a subterranean rodent which inhabits a semi-arid area in Northwestern Argentina. Although they live in underground burrows where environmental cycles are attenuated, they display robust, 24 h locomotor activity rhythms that are synchronized by light/dark cycles, both in laboratory and field conditions. The underground environment also poses energetic challenges (e.g. high-energy demands of digging, hypoxia, high humidity, low food availability) that have motivated thermoregulation studies in several subterranean rodent species. By using chronobiological protocols, the present work aims to contribute towards these studies by exploring day-night variations of thermoregulatory functions in tuco-tucos, starting with body temperature and its temporal relationship to locomotor activity. Animals showed daily, 24 h body temperature rhythms that persisted even in constant darkness and temperature, synchronizing to a daily light/dark cycle, with highest values occurring during darkness hours. The range of oscillation of body temperature was slightly lower than those reported for similar-sized and dark-active rodents. Most rhythmic parameters, such as period and phase, did not change upon removal of the running wheel. Body temperature and locomotor activity rhythms were robustly associated in time. The former persisted even after removal of the acute effects of intense activity on body temperature by a statistical method. Finally, regression gradients between body temperature and activity were higher in the beginning of the night, suggesting day-night variation in thermal conductance and heat production. Consideration of these day-night variations in thermoregulatory processes is beneficial for further studies on thermoregulation and energetics of subterranean rodents.

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“…Subterranean animals are interesting candidates for this line of research because even synchronization to day-night and the occurrence of light exposure is uncertain in nature.The circadian organization of subterranean species may provide interesting insights into whether and how synchronization to the external day and night occurs in this poorly cyclical natural environment [3] [4]. Members of the South American genus Ctenomys , popularly known as “tuco-tucos”, comprise the greatest number of species among subterranean rodents with more than 60 species ranging from 12° south latitude to Patagonia [5], [6]. Previous laboratory studies with solitary tuco-tucos from La Rioja, Argentina ( Ctenomys aff.…”

Section: Introductionmentioning

confidence: 99%

Field and Laboratory Studies Provide Insights into the Meaning of Day-Time Activity in a Subterranean Rodent (Ctenomys aff. knighti), the Tuco-Tuco

et al. 2012

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South American subterranean rodents (Ctenomys aff. knighti), commonly known as tuco-tucos, display nocturnal, wheel-running behavior under light-dark (LD) conditions, and free-running periods >24 h in constant darkness (DD). However, several reports in the field suggested that a substantial amount of activity occurs during daylight hours, leading us to question whether circadian entrainment in the laboratory accurately reflects behavior in natural conditions. We compared circadian patterns of locomotor activity in DD of animals previously entrained to full laboratory LD cycles (LD12∶12) with those of animals that were trapped directly from the field. In both cases, activity onsets in DD immediately reflected the previous dark onset or sundown. Furthermore, freerunning periods upon release into DD were close to 24 h indicating aftereffects of prior entrainment, similarly in both conditions. No difference was detected in the phase of activity measured with and without access to a running wheel. However, when individuals were observed continuously during daylight hours in a semi-natural enclosure, they emerged above-ground on a daily basis. These day-time activities consisted of foraging and burrow maintenance, suggesting that the designation of this species as nocturnal might be inaccurate in the field. Our study of a solitary subterranean species suggests that the circadian clock is entrained similarly under field and laboratory conditions and that day-time activity expressed only in the field is required for foraging and may not be time-dictated by the circadian pacemaker.

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

Cited by 30 publications

References 44 publications

Recurrent Amplifications and Deletions of Satellite DNA Accompanied Chromosomal Diversification in South American Tuco-tucos (Genus Ctenomys, Rodentia: Octodontidae): A Phylogenetic Approach

Recurrent Amplifications and Deletions of Satellite DNA Accompanied Chromosomal Diversification in South American Tuco-tucos (Genus Ctenomys, Rodentia: Octodontidae): A Phylogenetic Approach

Rhythmic 24 h Variation of Core Body Temperature and Locomotor Activity in a Subterranean Rodent (Ctenomys aff. knighti), the Tuco-Tuco

Field and Laboratory Studies Provide Insights into the Meaning of Day-Time Activity in a Subterranean Rodent (Ctenomys aff. knighti), the Tuco-Tuco

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