Abstract
The host specificities and systematics of North American Heligmosomoides species remain particularly uncertain. The primary aim of this study was to verify that a species described previously based only on morphology, H. thomomyos, from pocket gopher (Rodentia: Geomyidae) hosts in Oregon represented a monophyletic lineage. In order to address this aspect, as well as to further understand relationships and geographic patterns, we carried out phylogenetic, genetic diversity, and population dynamic analyses using partial 18S rRNA and COI mtDNA sequences of Heligmosomoides specimens. Phylogenetic analyses suggested that there are likely multiple Heligmosomoides species present in these hosts. This was supported by the high degree of divergence and differentiation found among populations, significant population structure between locations, and a modest positive association between geographic and genetic distances. This study serves as the first molecular characterization and first phylogenetic report of H. thomomyos, and documents two new host records for this parasite. The relationship of H. thomomyos among pocket gopher hosts and to other Heligmosomoides species, however, warrants continued study.
Highlights
The primary aims of this study were to: 1) deter mine whether nematodes putatively identified as H. thomomyos from Thomomys hosts revealed cryptic species, 2) better define the geomyid hosts parasitized by H. thomomyos, and 3) serve as the first molecular report and phylogenetic study for this species
This study provides further support for the cryptic diversity of nematodes and verifies that morphologically identified H. thomomyos from this study represent multiple distinctive lineages
The 18S Bayesian inference (BI) tree deviated from this expectation, as the placement of the H. polygyrus sequence from GenBank created a paraphyletic relationship among our samples
Summary
The systematics and host specificities of species belonging to the genus Heligmosomoides (Hall, 1916) is still ambiguous (Cable et al, 2006; Behnke and Harris, 2010; Clough and Råberg, 2014) and North American forms remain especially understudied (Harris et al, 2015). To describe with improved accuracy the bio diversity of helminths (intestinal ‘worms’) present in these hosts and to help resolve the phylogenies within Nematoda, molecular data must be accumulated. Such data can be used to infer population dynamics and, in conjunction with DNA from the host, help understand host-parasite associations. The primary aims of this study were to: 1) deter mine whether nematodes putatively identified as H. thomomyos from Thomomys hosts revealed cryptic species, 2) better define the geomyid hosts parasitized by H. thomomyos, and 3) serve as the first molecular report and phylogenetic study for this species. Population differentiation statistics were calculated to better understand the genetic diversity within and among populations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
