The largest known chromosome number for a mammal, in a South American desert rodent

González, Luis Carlos Contreras; Torres‐Mura, Juan C.; Spotorno, Ángel E.

doi:10.1007/bf01954248

Cited by 46 publications

(22 citation statements)

References 10 publications

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“…These ITBs could be remnant sequences of chromosomal rearrangement events, as have been suggested for some species (Meyne et al, 1990;Lee at al., 1993;Vermeesch et al, 1996). The lowest and highest chromosome numbers now known for rodents range from 2n = 9 and 10, described in the present paper for a new Akodon species found in Central Brazil, to 2n = 102, discovered in Tympanoctomys barrarae, a desert member of the family Octodontidae and an ancestor of the South American hystricognath rodents (Contreras et al, 1990).…”

Section: Discussionmentioning

confidence: 97%

Karyotype and chromosomal polymorphism of an undescribed Akodon from Central Brazil, a species with the lowest known diploid chromosome number in rodents

Silva

Yonenaga‐Yassuda²

1998

Cytogenet Genome Res

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The diploid chromosome number of 2n = 10 found in a new species of Akodon (Cricetidae, Rodentia) from two localities of the state of Mato Grosso, Central Brazil, represents the lowest chromosome number known for rodents. One female with nine chromosomes due to sex chromosome monosomy (2n = 9,XO) was also found. The karyotype comprises two large metacentric pairs (1 and 2); one large polymorphic pair (3), which could be acrocentric, submetacentric, or heterozygous as a result of a pericentric inversion; and one minute metacentric pair (4). The sex determination is of the XX/XY type. CBG, GTG, and RBG banding patterns, Ag-NORs, and meiotic data are presented. Fluorescence in situ hybridization with a (TTAGGG)₇ repeat as a probe revealed interstitial telomeric bands (ITBs) in two of the large pairs.

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Section: Discussionmentioning

confidence: 97%

Karyotype and chromosomal polymorphism of an undescribed Akodon from Central Brazil, a species with the lowest known diploid chromosome number in rodents

Silva

Yonenaga‐Yassuda²

1998

Cytogenet Genome Res

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“…Genome fusion is believed to have played a role in the recent evolution of only one mammal. The red viscacha rat, Tympanoctomys barrerae, possesses 100 autosomal chromosomes and two sex chromosomes, while its closest relatives possess only 55 autosomes and a single sex chromosome set (Contreras et al, 1990;Gallardo et al, 1999). In this case, it is notable that the apparent genome duplication includes neither the sex chromosomes nor a duplication of the autosomal 43rd chromosome pair, suggesting that these chromosomes may bear loci that are incompatible with polyploidy in vivo.…”

Section: Introductionmentioning

confidence: 90%

Tetraploid development in the mouse

Eakin

Behringer

2003

Developmental Dynamics

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Spontaneous duplication of the mammalian genome occurs in approximately 1% of fertilizations. Although one or more whole genome duplications are believed to have influenced vertebrate evolution, polyploidy of contemporary mammals is generally incompatible with normal development and function of all but a few tissues. The production of tetraploid (4n) embryos has become a common experimental manipulation in the mouse. Although development of tetraploid mice has generally not been observed beyond midgestation, tetraploid:diploid (4n:2n) chimeras are widely used as a method for rescuing extraembryonic defects. The tolerance of tissues to polyploidy appears to be dependent on genetic background. Indeed, the recent discovery of a naturally tetraploid rodent species suggests that, in rare genetic backgrounds, mammalian genome duplications may be compatible with the development of viable and fertile adults. Thus, the range of developmental potentials of tetraploid embryos remains in large part unexplored. Here, we review the biological consequences and experimental utility of tetraploid mammals, in particular the mouse. Developmental Dynamics 228:751-766, 2003.

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“…Moreover, the availability of limited human (HSA) vs. horse (ECA) painting data (Raudsepp et al, 1996;Raudsepp and Chowdhary, 2001) allow for the indirect identification of several segmental homologies that exist between the Rhinocerotidae, which have among the highest chromosome number in mammals, and man. (Higher diploid numbers have been recorded for the tetraploid rodent, Tympanoctomys barrerae 2n = 102, Contreras et al, 1990;Gallardo et al, 1999; the fish-eating rat, Anotomys leander 2n = 92, Gardner, 1971; the semiaquatic rodent Ichthyomys pittieri 2n = 92, Schmid et al, 1988; and the sigmodont rodent Zygodontomys 2n = 84-86, Mattevi et al, 2002). These data thereby provide a molecular cytogenetic basis to the correspondence within these species.…”

confidence: 99%

Cross-species chromosome painting in the Perissodactyla: delimitation of homologous regions in Burchell’s zebra (Equus burchellii) and the white (Ceratotherium simum) and black rhinoceros (Diceros bicornis)

Trifonov

Yang

Ferguson‐Smith

et al. 2003

Cytogenet Genome Res

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Conserved chromosomal segments in the black rhinoceros, Diceros bicornis (DBI, 2n = 84), and its African sister-species the white rhinoceros, Ceratotherium simum (CSI, 2n = 82), were detected using Burchell’s zebra (Equus burchellii, EBU, 2n = 44) chromosome-specific painting probes supplemented by a subset of those developed for the horse (Equus caballus, ECA, 2n = 64). In total 41 and 42 conserved autosomal segments were identified in C. simum and D. bicornis respectively. Only 21 rearrangements (20 fissions and 1 fusion) are necessary to convert the Burchell’s zebra karyotype into that of the white rhinoceros. One fission distinguishes the D. bicornis and C. simum karyotypes which, excluding heterochromatic differences, are identical in all respects at this level of resolution. Most Burchell’s zebra chromosomes correspond to two rhinoceros chromosomes although in four instances (EBU18, 19, 20 and 21) whole chromosome synteny has been retained among these species. In contrast, one rhinoceros chromosome (DBI1, CSI1) comprises two separate Burchell’s zebra chromosomes (EBU11 and EBU17). In spite of the high diploid numbers of the two rhinoceros species their karyotypes are surprisingly conserved offering a glimpse of the putative ancestral perissodactyl condition and a broader understanding of genome organization in mammals.

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The largest known chromosome number for a mammal, in a South American desert rodent

Cited by 46 publications

References 10 publications

Karyotype and chromosomal polymorphism of an undescribed <i>Akodon</i> from Central Brazil, a species with the lowest known diploid chromosome number in rodents

Karyotype and chromosomal polymorphism of an undescribed <i>Akodon</i> from Central Brazil, a species with the lowest known diploid chromosome number in rodents

Tetraploid development in the mouse

Cross-species chromosome painting in the Perissodactyla: delimitation of homologous regions in Burchell’s zebra <i>(Equus burchellii)</i> and the white <i>(Ceratotherium simum)</i> and black rhinoceros <i>(Diceros bicornis)</i>

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