@article{SchmidSteinleinWinking2016, author = {Schmid, Michael and Steinlein, Claus and Winking, Heinz}, title = {Multicolor Spectral Analyses of Mitotic and Meiotic Mouse Chromosomes Involved in Multiple Robertsonian Translocations. I. The CD/Cremona Hybrid Strain}, series = {Cytogenetic and Genome Research}, volume = {147}, journal = {Cytogenetic and Genome Research}, number = {4}, issn = {1424-8581}, doi = {10.1159/000444597}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-199013}, pages = {253-259}, year = {2016}, abstract = {Multicolor spectral analysis (spectral karyotyping) was applied to mitotic and male diakinetic chromosomes of hybrid mice carrying a unique system of 18 autosomal Robertsonian translocation chromosomes with alternating arm homologies. Only the autosomes 19 and the XY sex chromosomes are excluded from these Robertsonian translocations. The translocations, previously identified by conventional banding analyses, could be verified by spectral karyotyping. Besides the Robertsonian translocations, no other interchromosomal rearrangements were detected. In diakineses of male meiosis, the 18 metacentric Robertsonian translocation chromosomes form a very large meiotic 'superring'. The predictable, specific order of the chromosomes along this 'superring' was completely confirmed by multicolor spectral analysis. In the majority of diakineses analyzed, the free autosomal bivalent 19 and the XY sex bivalent form a conspicuous complex which tightly associates with the 12;14 Robertsonian translocation chromosome in the 'superring'.}, language = {en} } @article{SchmidSteinlein2016, author = {Schmid, Michael and Steinlein, Claus}, title = {Chromosome Banding in Amphibia. XXXIII. Demonstration of 5-Methylcytosine-Rich Heterochromatin in Anura}, series = {Cytogenetic and Genome Research}, volume = {148}, journal = {Cytogenetic and Genome Research}, number = {1}, issn = {1424-8581}, doi = {10.1159/000446141}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-199022}, pages = {35-43}, year = {2016}, abstract = {An experimental approach using monoclonal anti-5-methylcytosine (5-MeC) antibodies and indirect immunofluorescence was elaborated for detecting 5-MeC-rich chromosome regions in anuran chromosomes. This technique was applied to mitotic metaphases of 6 neotropical frog species belonging to 6 genera and 4 families. The hypermethylation patterns were compared with a variety of banding patterns obtained by conventional banding techniques. The hypermethylated DNA sequences are species-specific and located exclusively in constitutive heterochromatin. They are found in centromeric, pericentromeric, telomeric, and interstitial positions of the chromosomes and adjacent to nucleolus organizer regions. 5-MeC-rich DNA sequences can be embedded both in AT- and GC-rich repetitive DNA. The experimental parameters that have major influence on the reproducibility and quality of the anti-5-MeC antibody labeling are discussed.}, language = {en} } @article{SchmidSteinleinHaafetal.2014, author = {Schmid, Michael and Steinlein, Claus and Haaf, Thomas and Mijares-Urrutia, Abraham}, title = {Nascent ZW Sex Chromosomes in Thecadactylus rapicauda (Reptilia, Squamata, Phyllodactylidae)}, series = {Cytogenetic and Genome Research}, volume = {143}, journal = {Cytogenetic and Genome Research}, number = {4}, issn = {1424-8581}, doi = {10.1159/000366212}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-199041}, pages = {259-267}, year = {2014}, abstract = {The chromosomes of the turnip-tailed gecko Thecadactylus rapicauda from the Falc{\´o}n State in northern Venezuela were examined by means of conventional staining, a variety of banding techniques and in situ hybridization with an 18S + 28S rDNA probe. In female specimens, C-banding analyses detected a cryptic W sex chromosome-associated interstitial heterochromatic segment which is absent in the Z sex chromosome. These ZW sex chromosomes are considered to be in a nascent stage of morphological differentiation and are absent in T. rapicauda collected in Guatemala. The amount, location and fluorochrome affinities of constitutive heterochromatin, the position of the nucleolus organizer region, and the genome sizes of female and male individuals were determined. The previously published cytogenetic data on T. rapicauda are discussed.}, language = {en} } @article{SchmidSteinlein2016, author = {Schmid, Michael and Steinlein, Claus}, title = {Chromosome Banding in Amphibia. XXXIV. Intrachromosomal Telomeric DNA Sequences in Anura}, series = {Cytogenetic and Genome Research}, volume = {148}, journal = {Cytogenetic and Genome Research}, number = {2-3}, issn = {1424-8581}, doi = {10.1159/000446298}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196693}, pages = {211-226}, year = {2016}, abstract = {The mitotic chromosomes of 4 anuran species were examined by various classical banding techniques and by fluorescence in situ hybridization using a (TTAGGG)\(_n\) repeat. Large intrachromosomal telomeric sequences (ITSs) were demonstrated in differing numbers and chromosome locations. A detailed comparison of the present results with numerous published and unpublished data allowed a consistent classification of the various categories of large ITSs present in the genomes of anurans and other vertebrates. The classification takes into consideration the total numbers of large ITSs in the karyotypes, their chromosomal locations and their specific distribution patterns. A new category of large ITSs was recognized to exist in anuran species. It consists of large clusters of ITSs located in euchromatic chromosome segments, which is in clear contrast to the large ITSs in heterochromatic chromosome regions known in vertebrates. The origin of the different categories of large ITSs in heterochromatic and euchromatic chromosome regions, their mode of distribution in the karyotypes and evolutionary fixation in the genomes, as well as their cytological detection are discussed.}, language = {en} } @article{SchmidSteinleinLombetal.2016, author = {Schmid, Michael and Steinlein, Claus and Lomb, Christian and Sperling, Karl and Neitzel, Heidemarie}, title = {5-Methylcytosine-Rich Heterochromatin in the Indian Muntjac}, series = {Cytogenetic and Genome Research}, volume = {147}, journal = {Cytogenetic and Genome Research}, number = {4}, issn = {1424-8581}, doi = {10.1159/000444431}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196701}, pages = {240-246}, year = {2016}, abstract = {Two 5-methylcytosine (5-MeC)-rich heterochromatic regions were demonstrated in metaphase chromosomes of the Indian muntjac by indirect immunofluorescence using a monoclonal anti-5-MeC antibody. The metaphases were obtained from diploid and triploid cell lines. A major region is located in the 'neck' of the 3;X fusion chromosome and can be detected after denaturation of the chromosomal DNA with UV-light irradiation for 1 h. It is located exactly at the border of the X chromosome and the translocated autosome 3. A minor region is found in the centromeric region of the free autosome 3 after denaturing the chromosomal DNA for 3 h or longer. The structure and possible function of the major hypermethylated region as barrier against spreading of the X-inactivation process into the autosome 3 is discussed.}, language = {en} } @article{SchmidSteinleinYanoetal.2016, author = {Schmid, Michael and Steinlein, Claus and Yano, Cassia F. and Cioffi, Marcelo B.}, title = {Hypermethylated Chromosome Regions in Nine Fish Species with Heteromorphic Sex Chromosomes}, series = {Cytogenetic and Genome Research}, volume = {147}, journal = {Cytogenetic and Genome Research}, number = {2-3}, issn = {1424-8581}, doi = {10.1159/000444067}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196710}, pages = {169-178}, year = {2016}, abstract = {Sites and amounts of 5-methylcytosine (5-MeC)-rich chromosome regions were detected in the karyotypes of 9 Brazilian species of Characiformes fishes by indirect immunofluorescence using a monoclonal anti-5-MeC antibody. These species, belonging to the genera Leporinus, Triportheus and Hoplias, are characterized by highly differentiated and heteromorphic ZW and XY sex chromosomes. In all species, the hypermethylated regions are confined to constitutive heterochromatin. The number and chromosome locations of hypermethylated heterochromatic regions in the karyotypes are constant and species-specific. Generally, heterochromatic regions that are darkly stained by the C-banding technique are distinctly hypermethylated, but several of the brightly fluorescing hypermethylated regions merely exhibit moderate or faint C-banding. The ZW and XY sex chromosomes of all 9 analyzed species also show species-specific heterochromatin hypermethylation patterns. The analysis of 5-MeC-rich chromosome regions contributes valuable data for comparative cytogenetics of closely related species and highlights the dynamic process of differentiation operating in the repetitive DNA fraction of sex chromosomes.}, language = {en} } @article{SchmidSteinlein2015, author = {Schmid, Michael and Steinlein, Claus}, title = {Chromosome Banding in Amphibia. XXXII. The Genus Xenopus (Anura, Pipidae)}, series = {Cytogenetic and Genome Research}, volume = {145}, journal = {Cytogenetic and Genome Research}, number = {3-4}, issn = {1424-8581}, doi = {10.1159/000433481}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196727}, pages = {201-217}, year = {2015}, abstract = {Mitotic chromosomes of 16 species of the frog genus Xenopus were prepared from kidney and lung cell cultures. In the chromosomes of 7 species, high-resolution replication banding patterns could be induced by treating the cultures with 5-bromodeoxyuridine (BrdU) and deoxythymidine (dT) in succession, and in 6 of these species the BrdU/dT-banded chromosomes could be arranged into karyotypes. In the 3 species of the clade with 2n = 20 and 4n = 40 chromosomes (X. tropicalis, X. epitropicalis, X. new tetraploid 1), as well as in the 3 species with 4n = 36 chromosomes (X. laevis, X. borealis, X. muelleri), the BrdU/dT-banded karyotypes show a high degree of homoeology, though differences were detected between these groups. Translocations, inversions, insertions or sex-specific replication bands were not observed. Minor replication asynchronies found between chromosomes probably involve heterochromatic regions. BrdU/dT replication banding of Xenopus chromosomes provides the landmarks necessary for the exact physical mapping of genes and repetitive sequences. FISH with an X. laevis 5S rDNA probe detected multiple hybridization sites at or near the long-arm telomeric regions in most chromosomes of X. laevis and X. borealis, whereas in X. muelleri, the 5S rDNA sequences are located exclusively at the long-arm telomeres of a single chromosome pair. Staining with the AT base pair-specific fluorochrome quinacrine mustard revealed brightly fluorescing heterochromatic regions in the majority of X. borealis chromosomes which are absent in other Xenopus species.}, language = {en} } @article{SchmidEvansBogart2015, author = {Schmid, Michael and Evans, Ben J. and Bogart, James P.}, title = {Polyploidy in Amphibia}, series = {Cytogenetic and Genome Research}, volume = {145}, journal = {Cytogenetic and Genome Research}, number = {3-4}, issn = {1424-8581}, doi = {10.1159/000431388}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196730}, pages = {315-330}, year = {2015}, abstract = {This review summarizes the current status of the known extant genuine polyploid anuran and urodelan species, as well as spontaneously originated and/or experimentally produced amphibian polyploids. The mechanisms by which polyploids can originate, the meiotic pairing configurations, the diploidization processes operating in polyploid genomes, the phenomenon of hybridogenesis, and the relationship between polyploidization and sex chromosome evolution are discussed. The polyploid systems in some important amphibian taxa are described in more detail.}, language = {en} } @article{MatsudaUnoKondoetal.2015, author = {Matsuda, Yoichi and Uno, Yoshinobu and Kondo, Mariko and Gilchrist, Michael J. and Zorn, Aaron M. and Rokhsar, Daniel S. and Schmid, Michael and Taira, Masanori}, title = {A New Nomenclature of Xenopus laevis Chromosomes Based on the Phylogenetic Relationship to Silurana/Xenopus tropicalis}, series = {Cytogenetic and Genome Research}, volume = {145}, journal = {Cytogenetic and Genome Research}, number = {3-4}, issn = {1424-8581}, doi = {10.1159/000381292}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196748}, pages = {187-191}, year = {2015}, abstract = {Xenopus laevis (XLA) is an allotetraploid species which appears to have undergone whole-genome duplication after the interspecific hybridization of 2 diploid species closely related to Silurana/Xenopus tropicalis (XTR). Previous cDNA fluorescence in situ hybridization (FISH) experiments have identified 9 sets of homoeologous chromosomes in X. laevis, in which 8 sets correspond to chromosomes 1-8 of X. tropicalis (XTR1-XTR8), and the last set corresponds to a fusion of XTR9 and XTR10. In addition, recent X. laevis genome sequencing and BAC-FISH experiments support this physiological relationship and show no gross chromosome translocation in the X. laevis karyotype. Therefore, for the benefit of both comparative cytogenetics and genome research, we here propose a new chromosome nomenclature for X. laevis based on the phylogenetic relationship and chromosome length, i.e. XLA1L, XLA1S, XLA2L, XLA2S, and so on, in which the numbering of XLA chromosomes corresponds to that in X. tropicalis and the postfixes 'L' and 'S' stand for 'long' and 'short' chromosomes in the homoeologous pairs, which can be distinguished cytologically by their relative size. The last chromosome set is named XLA9L and XLA9S, in which XLA9 corresponds to both XTR9 and XTR10, and hence, to emphasize the phylogenetic relationship to X. tropicalis, XLA9_10L and XLA9_10S are also used as synonyms.}, language = {en} } @article{SchmidSteinleinFeichtingeretal.2014, author = {Schmid, Michael and Steinlein, Claus and Feichtinger, Wolfgang and Haaf, Thomas and Mijares-Urrutia, Abraham and Schargel, Walter E. and Hedges, S. Blair}, title = {Cytogenetic Studies on Gonatodes (Reptilia, Squamata, Sphaerodactylidae)}, series = {Cytogenetic and Genome Research}, volume = {144}, journal = {Cytogenetic and Genome Research}, number = {1}, issn = {1424-8581}, doi = {10.1159/000367929}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196753}, pages = {47-61}, year = {2014}, abstract = {Mitotic and meiotic chromosomes of 5 species of the reptile genus Gonatodes are described by means of conventional staining, banding analyses and in situ hybridization using a synthetic telomeric DNA probe. The amount, location and fluorochrome affinities of constitutive heterochromatin, the number and positions of nucleolus organizer regions, and the patterns of telomeric DNA sequences were determined for most of the species. The karyotypes of G. falconensis and G. taniae from northern Venezuela are distinguished by their extraordinarily reduced diploid chromosome number of 2n = 16, which is the lowest value found so far in reptiles. In contrast to most other reptiles, both species have exclusively large biarmed (meta- and submetacentric) chromosomes. Comparison of the karyotypes of G. falconensis and G. taniae with those of other Gonatodes species indicates that the exceptional 2n = 16 karyotype originated by a series of 8 centric fusions. The karyotypes of G. falconensis and G. taniae are further characterized by the presence of considerable amounts of (TTAGGG)n telomeric sequences in the centromeric regions of all chromosomes. These are probably not only relics of the centric fusion events, but a component of the highly repetitive DNA in the constitutive heterochromatin of the chromosomes. The genome sizes of 4 Gonatodes species were determined using flow cytometry. For comparative purposes, all previously published cytogenetic data on Gonatodes and other sphaerodactylids are included and discussed.}, language = {en} }