| species variation within the internal transcribed spacer (its) region of gyrodactylus (monogenea:gyrodactylidae) ribosomal rna genes. | the ribosomal internal transcribed spacer (its) region from individual gyrodactylus specimens was amplified by polymerase chain reaction (pcr). the reaction amplified the entire its1-5.8s-its2 region of the ribosomal rna gene cluster using primers that hybridize to the 3' terminus of the small subunit and the 5' terminus of the large subunit ribosomal rna genes. the pcr products from gyrodactylus salaris and gyrodactylus thymalli were cloned and sequenced. the gyrodactylus 5.8s gene was identifi ... | 1997 | 9105299 |
| molecular markers for gyrodactylids (gyrodactylidae: monogenea) from five fish families (teleostei). | thirty-one gyrodactylid species from five families of freshwater fish were examined and variable region v4 of the 18s small subunit ribosomal rna gene and ribosomal rna internal transcribed spacers its1 and its2 were sequenced. both the v4 region and spacers its1 and its2 proved useful for gyrodactylid diagnosis. sequences of these fragments exhibited interspecific variations and allowed clear determination at the species level. in some cases, the length of the its1 pcr fragment provided useful ... | 2001 | 11336756 |
| the susceptibility of grayling (thymallus thymallus) to experimental infections with the monogenean gyrodactylus salaris. | the pathogenic monogenean gyrodactylus salaris infecting atlantic salmon (salmo salar) is found to attach and reproduce under laboratory conditions on several species in the subfamily salmoninae other than the atlantic salmon. the gyrodactylid species gyrodactylus thymalli infecting grayling (thymallus thymallus) in another subfamily, thymallinae, is previously said to be very similar to g. salaris based on morphometry and genetical analysis which prompted the present laboratory experiments to t ... | 2001 | 11403770 |
| the use of host specificity, pathogenicity, and molecular markers to differentiate between gyrodactylus salaris malmberg, 1957 and g. thymalli zitnan, 1960 (monogenea: gyrodactylidae). | the validity of gyrodactylus thymalli has been questioned, based on its morphological and genetic resemblance to g. salaris. this taxonomic problem has practical implications regarding correct diagnosis of g. salaris, which has proved to be highly pathogenic to stocks of wild norwegian atlantic salmon. the host specificity and pathogenicity of g. salaris and g. thymalli were experimentally tested on salmon and grayling. both parasite species were able to infect, live and reproduce on both fish s ... | 2002 | 11860035 |
| mitochondrial dna variation of gyrodactylus spp (monogenea, gyrodactylidae) populations infecting atlantic salmon, grayling, and rainbow trout in norway and sweden. | approximately 800 bp of the mitochondrial cytochrome oxidase i (coi) gene were sequenced from 76 gyrodactylus specimens of 32 salmonid host populations, i.e. from salmo salar, thymallus thymallus, and oncorhynchus mykiss in norway, sweden and latvia. the coi sequences indicated a substantial intraspecific differentiation of gyrodactylus salaris and gyrodactylus thymalli. in total, 12 haplotypes were identified which group into five well supported clades, three clades with parasites from atlantic ... | 2003 | 14572510 |
| initial steps of speciation by geographic isolation and host switch in salmonid pathogen gyrodactylus salaris (monogenea: gyrodactylidae). | to test the hypothesis that host-switching can be an important step in the speciation of gyrodactylid monogenean flatworms, we inferred the phylogeny within a cluster of parasites morphologically close to gyrodactylus salaris malmberg 1957, collected from atlantic, baltic and white sea salmon (salmo salar), farmed rainbow trout (oncorhynchus mykiss), and grayling (thymallus thymallus) from northern europe. the internal transcribed spacer region of the nuclear ribosomal gene was sequenced for tax ... | 2004 | 15013741 |
| the use of morphometric characters to discriminate specimens of laboratory-reared and wild populations of gyrodactylus salaris and g. thymalli (monogenea). | gyrodactylus thymalli zitnan, 1960 and g. salaris malmberg, 1957 have an indistinguishable ribosomal internal transcribed spacer (its) dna sequence, but exhibit surprisingly high levels of intra- and interspecific sequence variation of the mitochondrial cytochrome oxidase i (co1) gene. to test whether different populations of these reportedly very similar species could be discriminated using morphometric methods, we examined the morphometry of four different populations representing different mi ... | 2004 | 15357403 |
| mitochondrial haplotype diversity of gyrodactylus thymalli (platyhelminthes; monogenea): extended geographic sampling in united kingdom, poland, and norway reveals further lineages. | in recent years, the mitochondrial haplotype diversity of the monogenean ectoparasites gyrodactylus salaris malmberg, 1957 on atlantic salmon and g. thymalli zitnan, 1960 on grayling has been studied intensively to understand the taxonomy and phylogeography of the two species. according to these studies, neither species can be considered monophyletic, but unfortunately, the geographic sampling has mostly been restricted to fennoscandia. only few samples from continental europe have been analysed ... | 2007 | 17216240 |
| the complete mitochondrial dna sequence of the monogenean gyrodactylus thymalli (platyhelminthes: monogenea), a parasite of grayling (thymallus thymallus). | we present the complete mitochondrial (mt) genome of gyrodactylus thymalli, a monogenean ectoparasite on grayling (thymallus thymallus). the circular genome is 14788 bp in size and includes all 35 genes recognized from other flatworm mt genomes. the overall a+t content of the mt genome is 62.8%. twenty regions of non-coding dna ranging from 1 to 111 bp in length were identified in addition to 2 highly conserved large non-coding regions 799 bp and 767 bp in size. compared to the recently describe ... | 2007 | 17559954 |
| mitochondrial dna variation of a natural population of gyrodactylus thymalli (monogenea) from the type locality river hnilec, slovakia. | the monogenean flatworm gyrodactylus thymalli (zitnan, helminthologia, 2:266-269, 1960) is considered a harmless ectoparasite on grayling (thymallus thymallus). the species is closely related to g. salaris malmberg, 1957 that causes severe gyrodactylosis on atlantic salmon (salmo salar) in many norwegian rivers. in this paper, we study the mitochondrial diversity of a g. thymalli population from one of the type localities hrable on river hnilec, slovakia. by sequencing parts of the mitochondrial ... | 2007 | 17694404 |
| hybrid origin of baltic salmon-specific parasite gyrodactylus salaris: a model for speciation by host switch for hemiclonal organisms. | host switching explains the high species number of ectoparasitic, viviparous, mainly parthenogenetic but potentially hermaphroditic flatworms of the genus gyrodactylus. the starlike mitochondrial phylogeny of gyrodactylus salaris suggested parallel divergence of several clades on grayling (also named as gyrodactylus thymalli) and an embedded sister clade on baltic salmon. the hypothesis that the parasite switched from grayling to salmon during the glacial diaspora was tested using a 493-bp nucle ... | 2007 | 17971088 |
| the mitochondrial genome of gyrodactylus derjavinoides (platyhelminthes: monogenea)--a mitogenomic approach for gyrodactylus species and strain identification. | systematists and evolutionary biologists are constantly on the lookout for new sources of characters to discriminate amongst taxa and estimate interrelationships within and between taxa. entire mitochondrial genomes provide a wealth of data, both at the nucleotide and amino acid level. molecular markers are of particular utility when applied to small, morphologically conserved taxa, as is the case for many monogenean ectoparasites of fish. gyrodactylus species display a considerable degree of an ... | 2008 | 18448274 |
| multi-centre testing and validation of current protocols for the identification of gyrodactylus salaris (monogenea). | despite routine screening requirements for the notifiable fish pathogen gyrodactylus salaris, no standard operating procedure exists for its rapid identification and discrimination from other species of gyrodactylus. this study assessed screening and identification efficiencies under real-world conditions for the most commonly employed identification methodologies: visual, morphometric and molecular analyses. obtained data were used to design a best-practice processing and decision-making protoc ... | 2010 | 20595003 |
| reconstructing mitochondrial genomes directly from genomic next-generation sequencing reads--a baiting and iterative mapping approach. | we present an in silico approach for the reconstruction of complete mitochondrial genomes of non-model organisms directly from next-generation sequencing (ngs) data-mitochondrial baiting and iterative mapping (mitobim). the method is straightforward even if only (i) distantly related mitochondrial genomes or (ii) mitochondrial barcode sequences are available as starting-reference sequences or seeds, respectively. we demonstrate the efficiency of the approach in case studies using real ngs data s ... | 2013 | 23661685 |
| genetic population structure of gyrodactylus thymalli (monogenea) in a large norwegian river system. | the extent of geographic genetic variation is the result of several processes such as mutation, gene flow, selection and drift. processes that structure the populations of parasite species are often directly linked to the processes that influence the host. here, we investigate the genetic population structure of the ectoparasite gyrodactylus thymalli žitňan, 1960 (monogenea) collected from grayling (thymallus thymallus l.) throughout the river glomma, the largest watercourse in norway. parts of ... | 2015 | 26463886 |
| microrna loci support conspecificity of gyrodactylus salaris and gyrodactylus thymalli (platyhelminthes: monogenea). | the monogenean flatworm gyrodactylus salaris is a serious threat to wild and farmed atlantic salmon stocks in norway. morphologically, the closely related but harmless gyrodactylus thymalli on grayling can hardly be distinguished from g. salaris. until now, molecular approaches could not resolve unambiguously whether g. salaris and g. thymalli represent just one polytypic species, two polytypic species or a complex of more than two species. in the first known genome-wide analysis utilizing 37 co ... | 2014 | 24998346 |