Phylogeny of hymenolepidids (Cestoda: Cyclophyllidea) from mammals: sequences of 18S rRNA and COI genes confirm major clades revealed by the 28S rRNA analyses.

The aim of the study is to test a hypothesis for the phylogenetic relationships among mammalian hymenolepidid tapeworms, based on partial (D1-D3) nuclear 28S ribosomal RNA (rRNA) genes, by estimating new molecular phylogenies for the group based on partial mitochondrial cytochrome c oxidase I (COI) and nuclear 18S rRNA genes, as well as a combined analysis using all three genes. New sequences of COI and 18S rRNA genes were obtained for Coronacanthus integrus, C. magnihamatus, C. omissus, C. vassilevi, Ditestolepis diaphana, Lineolepis scutigera, Spasskylepis ovaluteri, Staphylocystis tiara, S. furcata, S. uncinata, Vaucherilepis trichophorus and Neoskrjabinolepis sp. The phylogenetic analyses confirmed the major clades identified by Haukisalmi et al. (Zoologica Scripta 39: 631-641, 2010): Ditestolepis clade, Hymenolepis clade, Rodentolepis clade and Arostrilepis clade. While the Ditestolepis clade is associated with soricids, the structure of the other three clades suggests multiple evolutionary events of host switching between shrews and rodents. Two of the present analyses (18S rRNA and COI genes) show that the basal relationships of the four mammalian clades are branching at the same polytomy with several hymenolepidids from birds (both terrestrial and aquatic). This may indicate a rapid radiation of the group, with multiple events of colonizations of mammalian hosts by avian parasites.

Genetic diversity of liver flukes (Fasciola hepatica) from Eastern Europe.

The genetic diversity of liver fluke populations in three different countries from Eastern Europe (Greece, Bulgaria, and Poland) was determined and compared with available data from other countries. Specifically, SNPs from regions of two nuclear genes, 28S rDNA, ß-tubulin 3 and an informative region of the mitochondrial genome were examined. Two major lineages for the 28S rDNA gene based on the highly polymorphic 105th nucleotide position were found. These lineages were widely and almost equally spread not only through the countries studied but also in other investigated geographical areas. Two basic lineages and additional haplotypes were defined for the mtDNA gene region which consisted of the cytochrome c oxidase subunit III gene, transfer RNA histidine gene and cytochome b gene. The basic lineages were observed within Greek, Bulgarian, and Polish Fasciola hepatica populations but the distribution of additional haplotypes differed between the populations from the three countries. For the ß-tubulin 3 gene multiple polymorphic sites were revealed but no explicit clades. The SNPs were spread unequally in all studied geographical regions with an evident distinction between the Greek and Polish specimens. Additional genotypes for the 28S rDNA region as well as haplotypes of the mtDNA region that were typical for the Greek or Polish populations were observed. Significant polymorphisms for ß-tubulin 3 gene were displayed with decreasing percentage of presence within populations from Greece to Poland. There was an amino acid substitution in ß-tubulin 3 protein found only among Polish specimens. It is hypothesized that genotypic differences between Greek, Bulgarian, and Polish liver fluke populations are due to territorial division and genetic drift in past epochs.