We compared nucleotide sequences of the transcription-initiation region of five mouse ribosomal DNA (rDNA) clones. Two clones were isolated from Japanese wild mice, Mus musculus molossinus, and the other three from BALB/c mice originating in M. m. domesticus. Two BALB/c clones that are derived from the same chromosome are very similar, suggesting the occurrence of intrachromosomal homogenizatio...

Bathynellacea including the parabathynellid genus Allobathynella Morimoto & Miura, 1957 is commonly found across subterranean environment. The most species-rich known in Korea, and it now contains 23 species one subspecies from South Korea Japan. In this paper, we described a new of Danyang, Korea. danyangensis sp. nov. can be distinguished its congeners by presence five simple setae on ant...

We sequenced and compared the telomeric regions of linear rDNAs from vegetative macronuclei of several ciliates in the suborder Tetrahymenina. All telomeres consisted of tandemly repeated C4A2 sequences, including the 5' telomere of the 11 kb rDNA from developing macronuclei of Tetrahymena thermophila. Our sequence of the 11 kb 5' telomeric region shows that each one of a previously described p...

Abstract A small slug found in the tropical greenhouse of Science Museum (MUSE) Trento (Italy) turned out to be a species little-known systellommatophoran family Rathouisiidae. We undertook detailed comparative anatomical and molecular studies using specimens MUSE slug, Rathouisia sinensis, sequences other deposited GenBank conduct systematic phylogenetic assessment. Analysis genitalia R. sinen...

The macronucleus of the protozoan, Tetrahymena, is known to contain multiple rRNA genes which are not linked to the chromosomes. Here we present evidence that the germinal micronucleus of this organism contains a single gene for rRNA integrated into the chromosomal DNA. Unlike the extrachromosomal copies of the macronucleus, which are composed of a pair of reversely repeated sequences (a palind...

At anaphase onset, the protease separase triggers chromosome segregation by cleaving the chromosomal cohesin complex. Here, we show that cohesin destruction in metaphase is sufficient for segregation of much of the budding yeast genome, but not of the long arm of chromosome XII that contains the rDNA repeats. rDNA in metaphase, unlike most other sequences, remains in an undercondensed and topol...

Previous studies of the phylogeny of land plants based on analysis of 18S ribosomal DNA (rDNA) sequences have generally found weak support for the relationships recovered and at least some obviously spurious relationships, resulting in equivocal inferences of land plant phylogeny. We hypothesized that greater sampling of both characters and taxa would improve inferences of land plant phylogeny ...

This study focuses on the utility of molecular markers for the discrimination of closely related species in tintinnid ciliates. We analyzed the ecologically important genus Helicostomella by sequencing part of the large-subunit rDNA (LSU rDNA) and the 5.8S rDNA combined with the internally transcribed spacer regions 1 and 2 (5.8S rDNA-ITS) from forty-five individuals collected in NW and SW Atla...

BACKGROUND Wild ginseng, Panax ginseng Meyer, is an endangered species of medicinal plants. In the present study, we analyzed variations within the ribosomal DNA (rDNA) cluster to gain insight into the genetic diversity of the Oriental ginseng, P. ginseng, at artificial plant cultivation. METHODS The roots of wild P. ginseng plants were sampled from a nonprotected natural population of the Ru...

Quercus petraea and Quercus robur are two closely related oak species that frequently hybridize. We sequenced 70 clones containing the 5.8S and ITS2 regions of ribosomal DNA (rDNA) from these two species and did not detect a species-specific difference. Surprisingly, three divergent (up to 12.6%) rDNA families were identified in both species, indicating that they predate the speciation event. D...