The Lampbrush Chromosomes of<i>Rana Esculenta</i>L. (Amphibia — Anura)

Giorgi, Franco; Galleni, Lodovico

doi:10.1080/00087114.1972.10796470

Cited by 13 publications

(1 citation statement)

References 8 publications

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“…Lampbrush chromosomes from European water frogs were characterized in 1972 [ 26 ]. However reliable species identification was not performed and it was unclear whether analyzed frogs referred to P .…”

Section: Introductionmentioning

confidence: 99%

Optional Endoreplication and Selective Elimination of Parental Genomes during Oogenesis in Diploid and Triploid Hybrid European Water Frogs

et al. 2015

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Incompatibilities between parental genomes decrease viability of interspecific hybrids; however, deviations from canonical gametogenesis such as genome endoreplication and elimination can rescue hybrid organisms. To evaluate frequency and regularity of genome elimination and endoreplication during gametogenesis in hybrid animals with different ploidy, we examined genome composition in oocytes of di- and triploid hybrid frogs of the Pelophylax esculentus complex. Obtained results allowed us to suggest that during oogenesis the endoreplication involves all genomes occurring before the selective genome elimination. We accepted the hypothesis that only elimination of one copied genome occurs premeiotically in most of triploid hybrid females. At the same time, we rejected the hypothesis stating that the genome of parental species hybrid frogs co-exist with is always eliminated during oogenesis in diploid hybrids. Diploid hybrid frogs demonstrate an enlarged frequency of deviations in oogenesis comparatively to triploid hybrids. Typical for hybrid frogs deviations in gametogenesis increase variability of produced gametes and provide a mechanism for appearance of different forms of hybrids.

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Section: Introductionmentioning

confidence: 99%

Optional Endoreplication and Selective Elimination of Parental Genomes during Oogenesis in Diploid and Triploid Hybrid European Water Frogs

et al. 2015

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Working map of the lampbrush chromosomes of Xenopus tropicalis: A new tool for cytogenetic analyses

Penrad-Mobayed

Jamil

Kanhoush

et al. 2009

Developmental Dynamics

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The amphibian Xenopus tropicalis, whose genome has been recently sequenced, has become an important model organism for vertebrate developmental genetics. The development of cytogenetic tools in this new model organism should contribute to an understanding of the organization of the amphibian genome and the mapping of a variety of loci of interest. In this respect, oocyte lampbrush chromosomes are particularly useful for the localization of genomic sequences expressed during oogenesis. We have constructed a working map of X. tropicalis lampbrush chromosomes, which allows the 10 bivalents of the oocyte karyotype to be readily identified by distinctive combinations of specific landmark structures composed of lateral loops, spheres, and granules. We have also established the patterns of RNA Pol III sites over the chromosomes by immunofluorescence using antibodies directed against two Pol III subunits. Specific staining patterns were found for each chromosome, which constitute a supplementary tool for their identification.

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Lampbrush and mitotic chromosomes of the hemiclonally reproducing hybrid Rana esculenta and its parental species

et al. 1990

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Mitotic chromosomes of the European water frogs Rana ridibunda and Rana lessonae, the parental species of Rana esculenta, differ significantly in their centromeric regions: when C-banded or when made fluorescent, the centromeres of R. ridibunda (and of ridibunda chromosomes in R. esculenta) are visible as a conspicuous dark granule or as a conspicuous fluorescent spot; the centromeres of R. lessonae (and of the lessonae chromosomes in R. esculenta) are inconspicuous or not fluorescent. Lampbrush chromosomes of these three taxa are described in detail for the first time; those of R. ridibunda and R. lessonae differ significantly in morphostructural characters such as conspicuousness of centromeres and number, form, and location of giant loops as well as in chiasma frequency. Chromosomes of the two parental species can thus be distinguished when present in lampbrush complements of hybrids. Reproduction in both sexes of natural R. esculenta lineages is hemiclonal: only the unrecombined genome of one parental species, usually R. ridibunda, is transmitted to haploid gametes (hybridogenesis). In 18 hybrids from natural populations of Poland, somatic tissues had allodiploid complements with chromosomes from each parental species. In contrast, spermatocytes I of five males and oocytes I of seven of eight females (221 of 222 oocytes) were autodiploid and contained only R. ridibunda chromosomes that formed n bivalents. These 12 hybrids thus were hybridogenetic. A single female hybrid had oocytes I (33 of 34) with genomes of both parental species; they showed various disturbances including tetraploidy, reduced number of chiasmata, and incomplete synapsis resulting in univalents. This individual thus was not hybridogenetic. The irregular lampbrush patterns indicate that such hybrids will have severely reduced fertility and most of their successful gametes will result in allotriploid progeny.

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The Lampbrush Chromosomes ofRana EsculentaL. (Amphibia — Anura)

Cited by 13 publications

References 8 publications

Optional Endoreplication and Selective Elimination of Parental Genomes during Oogenesis in Diploid and Triploid Hybrid European Water Frogs

Optional Endoreplication and Selective Elimination of Parental Genomes during Oogenesis in Diploid and Triploid Hybrid European Water Frogs

Working map of the lampbrush chromosomes of Xenopus tropicalis: A new tool for cytogenetic analyses

Lampbrush and mitotic chromosomes of the hemiclonally reproducing hybrid Rana esculenta and its parental species

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