The radiation of Haliotrema (Monogenea: Dactylogyridae: Ancyrocephalinae): molecular evidence and explanation inferred from LSU rDNA sequences

Abstract

The D1-D2 domains of LSU rDNA were used to reconstruct the phylogenetic relationships within the Ancyrocephalinae (Monogenea: Dactylogyridae) utilizing maximum-parsimony (MP), maximum-likelihood (ML), minimum evolution (ME) and neighbour-joining (NJ) methods. A total of 32 monogenean taxa were examined in the present study, including 9 Haliotrema species and 13 other species representing the Ancyrocephalinae, 4 Thaparocleidus species representing the Ancylodiscoididae, and 6 species representing the Diplectanidae which were used as multiple outgroups. All 4 analyses (i.e. MP, ML, ME and NJ) inferred the same interrelationship pattern: (Diplectanidae, (Ancylodiscoididae, Dactylogyridae)) with high bootstrap support. However, 9 Haliotrema species were dispersed to form 4 clades together with species from other genera, indicating the apparent non-monophyly of Haliotrema. Three major groups were defined based on reconstructed phylogenetic trees to explain the radiation of Haliotrema species. The morphology of the reproductive organ, particularly the male copulatory organ (MCO), was discussed to further understand the formation of each group. (1) Results of the present study indicated an intimate relationship among Metahaliotrema (2 species), Protogyrodactylus (4 species) and Haliotrema (2 of 9 species), and notably, all these species share vagina-absence. (2) Based on the present molecular analyses and the morphological characters of the MCO, we propose to transfer H. spirotubiforum and the undetermined Haliotrema sp. ZHDDb to Euryhaliotrema as new combinations. (3) We propose to erect a new genus to accommodate the Haliotrema species with horn-like shaped MCO. Taxonomic implications of the present molecular phylogenetic analyses are discussed. A wider range of taxa and more DNA markers displaying various evolutionary rates should be used to estimate phylogenetic relationships among species within the Ancyrocephalinae and Ancylodiscoididae in further studies.

Non-lethal detection of DNA from Cichlidogyrus spp. (Monogenea, Ancyrocephalinae) in gill mucus of the Nile tilapia Oreochromis niloticus

“…The 5 primer sets amplified se quences which had ~91 to 98% homology with the original region D1 to D2 of LSU rDNA (28S gene) (DQ157660.1) GenBank (Wu et al 2006). The amplified sequences also matched the same set of parasites previously described: the LSU rDNA region of C. cubitus (Wu et al 2007).…”

“…Primers were synthesized on the basis of the region D1 to D2 of the large subunit (LSU) 28S rDNA gene of Cichlidogyrus sclerosus (DQ157660.1) (Wu et al 2006) with the aid of the primer3 (v.0.40) software program (Rozen & Skaletsky 2000). The following criteria were applied to the design of the new primers: GC content from 45 to 60%; minimal secondary structure; no primer-dimers; melting temperature (T m ) between 50 and 70°C; and a length of 20 to 24 bases.…”

“…DNA Sequences of the PCR products obtained with the 5 sets of primers were submitted to GenBank to check against the genome of Cichlidogyrus sclerosus (D1 to D2 region of the LSU 28S rDNA gene from which the primers were designed). The PCR products obtained with all 5 sets of primers had ~95 to 100% homology with the corresponding region (DQ 15 7660.1 GenBank) (Wu et al 2006). The amplicons also matched the LSU rDNA region of C. cu bitus (HQ010037.1), C. falcifer (HQ 010024.1), C. tila piae (HQ010029.1), C. arthracanthus (HQ010022.1), C. er gensi (HQ 01 00 38.1), C. pouyaudi (HQ010039.1), C. di gitatus (HQ 01 0023.1), C. lon gi cirrus (HQ0100 26.1) C. acerbus (HQ 010036.1), Cichlidogyrus sp.…”

“…A small region (25% of total coverage) showed > 90% homology with the D1 to D2 regions of LSU rDNA from Scutogyrus longicornis (DQ157659.1) (Wu et al 2006) and the LSU rDNA region of S. longicornis (HQ010035.1) (Mendlová et al 2010). The (Tingbao et al 2006).…”

“…obs.). Secondary infection by bacteria and fungus is common in tissues that have been damaged by monogeneans (Wu et al 2006).…”