background:   human fascioliasis is an important health problem in the province of gilan, at the caspian sea, iran. there is the overlapping of both fasciolid species, fasciola hepatica and f. gigantica . recent studies on both domestic animal and lym­naeid infection furnished evidence suggesting that f. gigantica and radix gedrosiana may be the main fasciolid and lym­naeid involved in the dise...

background: the phylogenetic location of chinese spirometra sparganum isolates remains unclear. the aim of this study was to explore the phylogenetic location of the spirometra sparganum isolates from china. methods: the 28s ribosomal dna (rdna) d1 sequences of 14 spirometra sparganum isolates collected from thirteen locations in china were analyzed by using neighbor-joining (nj), maximum parsi...

Sequences of the complete nuclear ribosomal DNA (rDNA) gene from five individual Paramphistomum cervi were determined for the first time. The five complete rDNA sequences, which included the 18S rDNA, the internal transcribed spacer 1 (ITS1), the 5.8S rDNA, the internal transcribed spacer 2 (ITS2), the 28S rDNA, and the intergenic spacer (IGS) regions, had a length range of 8,493-10,221 bp. The...

The ribosomal DNA (rDNA) in Tetrahymena thermophila is a 21-kilobase-pair palindromic DNA molecule that replicates autonomously in the macronucleus and is maintained at the level of about 10,000 copies per macronucleus. The rDNA of inbred strain C3 outreplicates the rDNA of inbred strain B in most B/C3 heterozygous macronuclei, generating macronuclei containing exclusively C3 rDNA sequences. In...

The recent introduction of molecular techniques in eukaryotic microbial diversity studies, in particular those based in the amplification and sequencing of small-subunit ribosomal DNA (SSU rDNA), has revealed the existence of an unexpected variety of new phylotypes. The taxonomic ascription of the organisms bearing those sequences is generally deduced from phylogenetic analysis. Unfortunately, ...

sequence data of a recent coi barcoding study on fish from the nayband national park in the persian gulf showed relatively high sequence divergence among nominal gerres filamentosus specimens. the sequences grouped into two clusters, signaling the possible existence of cryptic species. the clustering pattern was corroborated by results of 16s rdna sequencing. we investigated the hypothesis that...

Studies on the evolutionary history of ascomycetes in terms of time scale will help to understand historical patterns that shape their biodiversity. Until now most of dating studies of ascomycetes have focused on major events in fungal evolution but not on divergence events within smaller groups of fungi e.g. within Sordariomycetes. We used molecular dating to estimate the time of separation of...

Approximately 35% of the human genome can be identified as sequence devoid of a selected-effect function, and not derived from transposable elements or repeated sequences. We provide evidence supporting a known origin for a fraction of this sequence. We show that: 1) highly degraded, but near full length, ribosomal DNA (rDNA) units, including both 45S and Intergenic Spacer (IGS), can be found a...