title: A comparative study of karyotypes and chromosomal location of rDNA genes in important liver flukes Fasciola hepatica and Fascioloides magna (Trematoda: Fasciolidae).
abstract: Chromosomal characteristics, i.e., number, size, morphology, and location of ribosomal DNA (rDNA) clusters were examined in two medically important liver flukes, Fasciola hepatica and Fascioloides magna (Fasciolidae), using conventional Giemsa staining and fluorescent in situ hybridization (FISH) with ribosomal 18S rDNA probe. A comparison of F. magna and F. hepatica karyotypes confirmed significant differences in all chromosomal features. Whilst the karyotype of F. hepatica comprised ten pairs of chromosomes (one metacentric and nine medium-sized subtelocentrics and submetacentrics; 2n = 20, n = 1 m + 5 sm + 4 st; TCL = 49.9 μm), the complement of F. magna was composed of 11 pairs of medium-sized subtelocentrics and submeta-metacentrics (2n = 22, n = 9 st + 1 sm + 1 sm-m; TCL = 35.2 μm). Noticeable differences were found mainly in length and morphology of first chromosome pair. It was metacentric and 9.0 μm long in F. hepatica while subtelocentric and 4.7 μm long in F. magna. Although FISH with rDNA probe revealed a single cluster of ribosomal genes in both species, conspicuous interspecific differences were displayed by chromosomal location of ribosomal loci (i.e., NORs). The signals were found on short arms of fifth homologous pair in F. hepatica; however, they were detected in pericentromeric regions of the long arms of tenth pair in F. magna. The observed cytogenetic differences were interpreted in terms of karyotype evolution of fasciolid flukes; F. hepatica may be regarded phylogenetically younger than F. magna. The present paper provides a pilot study on molecular cytogenetics within a group of hermaphroditic digenetic flukes.
authors.affiliation: Parasitological Institute, Slovak Academy of Sciences, Hlinkova 3, 04001 Košice, Slovakia. reblan@saske.sk
authors.forename: Marianna
authors.initials: M
authors.lastname: Reblánová
authors.forename: Marta
authors.initials: M
authors.lastname: Spakulová
authors.forename: Martina
authors.initials: M
authors.lastname: Orosová
authors.forename: Ivica
authors.initials: I
authors.lastname: Králová-Hromadová
authors.forename: Eva
authors.initials: E
authors.lastname: Bazsalovicsová
authors.forename: Dušan
authors.initials: D
authors.lastname: Rajský
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000469:parasitology; D002875:Chromosomes / Q000737:chemistry / Q000235:genetics / Q000648:ultrastructure*; D003582:Cytogenetics / Q000379:methods*; D015342:DNA Probes / Q000737:chemistry / Q000235:genetics; D003670:Deer; D005210:Fasciola hepatica / Q000235:genetics* / Q000302:isolation & purification; D005211:Fascioliasis / Q000469:parasitology* / Q000662:veterinary; D005212:Fasciolidae / Q000235:genetics* / Q000302:isolation & purification; D005213:Fascioloidiasis / Q000469:parasitology*; D017404:In Situ Hybridization, Fluorescence; D059785:Karyotype; D007621:Karyotyping; D008099:Liver / Q000469:parasitology; D008938:Mitosis; D009697:Nucleolus Organizer Region / Q000737:chemistry / Q000235:genetics / Q000648:ultrastructure*; D010802:Phylogeny; D010865:Pilot Projects; D012337:RNA, Ribosomal, 18S / Q000737:chemistry / Q000235:genetics; D018154:Slovakia; D013045:Species Specificity
chemical_list: D015342:DNA Probes; D012337:RNA, Ribosomal, 18S