Phylogenetic relationships among species of Contracaecum Railliet & Henry, 1912 and Phocascaris Høst, 1932 (Nematoda[ratio ]Ascaridoidea) based on nuclear rDNA sequence data

Abstract

Nuclear-encoded large-subunit ribosomal DNA sequences were used to infer a phylogenetic hypothesis for 17 taxa (16 nominal species) of the genera Contracaecum and Phocascaris. Phylogenetic trees based on these data have been used to assess the validity of the taxonomic distinction between these genera, which was based on the presence or absence of certain structural features, rather than on explicit hypotheses of evolutionary history. Phylogenetic hypotheses based on parsimony, likelihood, and neighbor-joining analyses of these sequence data strongly support the hypothesis that species of Phocascaris are nested within the clade of Contracaecum species hosted by phocid seals, and are more closely related to species of the Contracaecum osculatum complex than to other Contracaecum species. Alternative tree topologies representing Phocascaris as not nested within the C. osculatum complex were significantly worse interpretations of these sequence data. Phylogenetic analysis also provides strong support for the monophyly of all taxa (Contracaecum and Phocascaris) from phocid seals, which is consistent with Berland's (1964) proposal that such species form a natural group; however, his proposal to recognize all species in phocid seals as Phocascaris, with all species from birds as Contracaecum would result in a paraphyletic Contracaecum, according to the molecular phylogenetic hypothesis.

Electrophoretic detection of population variation withinContracaecum ogmorhini (Nematoda: Ascaridoidea: Anisakidae)

“…2) with those of members of the C. osculatum complex [9] and Contracaecum eudyptulae (see [16]). Pairwise comparisons among all sequences revealed nucleotide differences of 0-15.8% in the ITS-1 and of 0-33.1% in the ITS-2 (Table 1).…”

“…Pairwise comparisons among all sequences revealed nucleotide differences of 0-15.8% in the ITS-1 and of 0-33.1% in the ITS-2 (Table 1). In addition to CoZC being genetically distinct from CoAPP/CoAPD, C. ogmorhini was genetically more similar to C. eudyptulae from bird than it was to members of the C. osculatum complex from different spe- [9] and Contracaecum eudyptulae (Ceud) [16] were included in the alignment for comparative purposes. The location of the BstN1 restriction site is underlined.…”

Molecular characterization of Baylisascaris devosi Sprent, 1952 (Ascaridoidea, Nematoda) from Kamchatka sables

“…Another pair of primers JB3_F (5'-TTT TTT GGG CAT CCT GAG GTT TAT -3') and JB7GED_R (5'-ATC AGG ATA ATC CAA ATA YTT WCG WGG -3') was used to amplify 650 bp long 3' portion of the same CoxI gene of mtDNA (Bowles et al, 1992;Derycke et al, 2010). PCR cycling parameters included primary denaturation at 95 °C for 5 min followed by 35 cycles of 94 °C for 45 s, 56 °C for 60 s and 72 °C for 70 s. A pair of primers LSU391 (5'-AGC GGA GGA AAA GAA ACT AA -3') and LSU501 (5'TCG GAA GGA ACC AGC TAC TA-3') were used to amplify a 1100 bp long sequence of D2D3 expansion segment of LSU rDNA (Nadler et al, 2000). PCR cycling parameters included denaturation at 95 °C for 4 min, followed by 35 cycles of 94 °C for 30 sec, 49 °C for 30 sec, and 72 °C for 70 s.…”

Phylogenetic Analysis of the Metastrongyloidea (Nematoda: Strongylida) Inferred From Ribosomal Rna Gene Sequences

“…Approximately 1,750 bp of the 18S or SSU rDNA was amplified in 2 overlapping pieces using primers 47 forward (5Ј-CCCGATTGATTCTGTCGGC) and 112 reverse (5Ј-GGCTGCTGGCACCAGACTTGC) with the overlapping primers 135 forward (5Ј-CGGAGAGGGAGCCTGAGAAACGGC) and 136 reverse (5Ј-TGATCCTTCTGCAGGTTCACCTAC). A 950-bp fragment of the 5Ј end of 28S or LSU rDNA containing the D2 and D3 domains was amplified using primers 391 forward (5Ј-AGCGGAGGAAAAGAAAC-TAA) and 501 reverse (5Ј-TCGGAAGGAACCAGCTACTA), as described in Nadler et al (2000). The third amplified region consisted of 850-900 bp of the 3Ј end of the LSU rDNA.…”