TY  - JOUR
A1  - Schmid, Michael
A1  - Steinlein, Claus
T1  - Chromosome Banding in Amphibia. XXXIII. Demonstration of 5-Methylcytosine-Rich Heterochromatin in Anura
JF  - Cytogenetic and Genome Research
N2  - 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.
KW  - Anura
KW  - heterochromatin
KW  - hypermethylated DNA
KW  - immunofluorescence
KW  - 5-Methylcytosine
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-199022
SN  - 1424-8581
SN  - 1424-859X
N1  - This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.
VL  - 148
IS  - 1
ER  - 
TY  - JOUR
A1  - Schmid, Michael
A1  - Steinlein, Claus
T1  - Chromosome Banding in Amphibia. XXXIV. Intrachromosomal Telomeric DNA Sequences in Anura
JF  - Cytogenetic and Genome Research
N2  - 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 A detailed comparison of the present results with numerous published and unpublished data allowed a consistent classification of the various categories of large ITSs present in the genomes of anurans and other vertebrates.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.
KW  - heterochromatin
KW  - intrachromosomal telomeric sequences
KW  - Anura
KW  - euchromatin
KW  - evolutionary fixation
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-196693
SN  - 1424-8581
SN  - 1424-859X
N1  - This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.
VL  - 148
IS  - 2-3
ER  -