Intra- and interspecific genetic diversity of New Zealand hairworms (Nematomorpha)

Parasitology ◽  
2017 ◽  
Vol 144 (8) ◽  
pp. 1026-1040 ◽  
Author(s):  
ZACHARY J. C. TOBIAS ◽  
ARUN K. YADAV ◽  
ANDREAS SCHMIDT-RHAESA ◽  
ROBERT POULIN

SUMMARYHairworms (Nematomorpha) are a little-known group of parasites, and despite having been represented in the taxonomic literature for over a century, the implementation of molecular genetics in studies of hairworm ecology and evolution lags behind that of other parasitic taxa. In this study, we characterize the genetic diversity of the New Zealand nematomorph fauna and test for genetic structure within the most widespread species found. We provide new mitochondrial and nuclear ribosomal sequence data for three previously described species from New Zealand:Gordius paranensis, Parachordodes diblastusandEuchordodes nigromaculatus. We also present genetic data on a previously reported but undescribedGordiussp., as well as data from specimens of a newGordionussp., a genus new for New Zealand. Phylogenetic analyses of CO1 and nuclear rDNA regions correspond with morphological classification based on scanning electron microscopy, and demonstrate paraphyly of the genusGordionusand the potential for cryptic species withinG. paranensis. Population-level analyses ofE. nigromaculatusshowed no genetic differentiation among sampling locations across the study area, in contrast to previously observed patterns in known and likely definitive hosts. Taken together, this raises the possibility that factors such as definitive host specificity, intermediate host movement, and passive dispersal of eggs and larvae may influence host–parasite population co-structure in hairworms.

2019 ◽  
Vol 191 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Matt H Buys ◽  
Richard C Winkworth ◽  
Peter J de Lange ◽  
Peter G Wilson ◽  
Nora Mitchell ◽  
...  

Abstract Leptospermum scoparium (Myrtaceae) is a morphologically highly variable species found in mainland Australia, Tasmania and New Zealand. For example, in New Zealand up to six morphologically distinct varieties of this species have been described, although only two (var. scoparium and var. incanum) are now formally recognized. In the present study we provide a first examination of genetic diversity in this culturally and commercially important species with the aim of gaining insights into its origins and evolution. We used anchored hybrid enrichment to acquire sequence data from 485 orthologous low-copy nuclear loci for 27 New Zealand and three Australian accessions of L. scoparium and representatives of several other Leptospermum spp. The final concatenated data matrix contained 421 687 nucleotide positions of which 55 102 were potentially informative. Despite the relative large data set, our analyses suggest that a combination of low and incompatible data signal limits the resolution of relationships among New Zealand populations of L. scoparium. Nevertheless, our analyses are consistent with genetic diversity being geographically structured, with three groups of L. scoparium recovered. We discuss the evolutionary and taxonomic implications of our findings.


2020 ◽  
Vol 117 (29) ◽  
pp. 17104-17111
Author(s):  
Nicola F. Müller ◽  
Ugnė Stolz ◽  
Gytis Dudas ◽  
Tanja Stadler ◽  
Timothy G. Vaughan

Reassortment is an important source of genetic diversity in segmented viruses and is the main source of novel pathogenic influenza viruses. Despite this, studying the reassortment process has been constrained by the lack of a coherent, model-based inference framework. Here, we introduce a coalescent-based model that allows us to explicitly model the joint coalescent and reassortment process. In order to perform inference under this model, we present an efficient Markov chain Monte Carlo algorithm to sample rooted networks and the embedding of phylogenetic trees within networks. This algorithm provides the means to jointly infer coalescent and reassortment rates with the reassortment network and the embedding of segments in that network from full-genome sequence data. Studying reassortment patterns of different human influenza datasets, we find large differences in reassortment rates across different human influenza viruses. Additionally, we find that reassortment events predominantly occur on selectively fitter parts of reassortment networks showing that on a population level, reassortment positively contributes to the fitness of human influenza viruses.


Plant Disease ◽  
2016 ◽  
Vol 100 (2) ◽  
pp. 276-286 ◽  
Author(s):  
M. Crespo ◽  
F. M. Cazorla ◽  
A. de Vicente ◽  
E. Arrebola ◽  
J. A. Torés ◽  
...  

Mango malformation disease (MMD) has become an important global disease affecting this crop. The aim of this study was to identify the main causal agents of MMD in the Axarquía region of southern Spain and determine their genetic diversity. Fusarium mangiferae was previously described in the Axarquía region but it represented only one-third of the fusaria recovered from malformed trees. In the present work, fusaria associated with MMD were analyzed by arbitrary primed polymerase chain reaction (ap-PCR), random amplified polymorphic DNA (RAPD), vegetative compatibility grouping (VCG), a PCR screen for mating type idiomorph, and phylogenetic analyses of multilocus DNA sequence data to identify and characterize the genetic diversity of the MMD pathogens. These analyses confirmed that 92 of the isolates were F. tupiense, which was previously only known from Brazil and Senegal. In addition, two isolates of a putatively novel MMD pathogen were discovered, nested within the African clade of the Fusarium fujikuroi species complex. The F. tupiense isolates all belonged to VCG I, which was first described in Brazil, and the 11 isolates tested showed pathogenicity on mango seedlings. Including the prior discovery of F. mangiferae, three exotic MMD pathogenic species have been found in southern Spain, which suggests multiple independent introductions of MMD pathogens in the Axarquía region.


2006 ◽  
Vol 37 (3) ◽  
pp. 335-350 ◽  
Author(s):  
Jakob Damgaard

AbstractThis study addresses the phylogenetic relationships within and between two widespread Palaearctic pond skater species, Gerris costae and G. thoracicus, by including new DNA sequence data from the Central Asian G. sahlbergi, traditionally assigned as a close relative of G. costae. The results support the assignment of G. costae and G. thoracicus to two individual species groups that are not closely related, but also that G. sahlbergi is nested within G. costae (including subspecies costae, fieberi and poissoni) thus suggesting a new subspecific rank as G. c. sahlbergi. A broad geographical sampling of mitochondrial DNA from populations of G. thoracicus and G. costae (incl. G. c. sahlbergi) shows that the two species are strikingly similar in terms of genetic diversity and lack of geographical substructure, thus adding further evidence for the G. costae group comprising a single, widespread species.


2019 ◽  
Author(s):  
Nicola F. Müller ◽  
Ugnė Stolz ◽  
Gytis Dudas ◽  
Tanja Stadler ◽  
Timothy G. Vaughan

AbstractReassortment is an important source of genetic diversity in segmented viruses and is the main source of novel pathogenic influenza viruses. Despite this, studying the reassortment process has been constrained by the lack of a coherent, model-based inference framework. We here introduce a novel coalescent based model that allows us to explicitly model the joint coalescent and reassortment process. In order to perform inference under this model, we present an efficient Markov chain Monte Carlo algorithm to sample rooted networks and the embedding of phylogenetic trees within networks. Together, these provide the means to jointly infer coalescent and reassortment rates with the reassortment network and the embedding of segments in that network from full genome sequence data. Studying reassortment patterns of different human influenza datasets, we find large differences in reassortment rates across different human influenza viruses. Additionally, we find that reassortment events predominantly occur on selectively fitter parts of reassortment networks showing that on a population level, reassortment positively contributes to the fitness of human influenza viruses.


Phytotaxa ◽  
2021 ◽  
Vol 490 (1) ◽  
pp. 35-46
Author(s):  
WENDY A. NELSON ◽  
KATE F. NEILL ◽  
BRENTON A. TWIST ◽  
JUDY E. SUTHERLAND

A new genus in the order Sporolithales (Corallinophycidae, Rhodophyta), Roseapetra farriae gen. et sp. nov. is described, based on material from northern New Zealand. Previously placed in the genus Heydrichia on the basis of morpho-anatomical characters, phylogenetic analyses have shown that this northern New Zealand taxon is not resolved with either Heydrichia or Sporolithon, the two genera currently recognized in this order. Roseapetra displays the key diagnostic features of the order, namely the production of cruciately divided tetrasporangia singly within calcified sporangial compartments. In Roseapetra the tetrasporangia are surrounded by an involucre, and mature tetrasporangia are subtended by up to three stalk cells. The tetrasporangial compartments are shed once spores have been released. Gametangial conceptacles are not shed but become buried, with secondary meristem producing lens-like areas of regrowth. While there are several morpho-anatomical characters that separate Roseapetra and Sporolithon, there are none that can be used to distinguish Roseapetra from Heydrichia: recognition of Roseapetra requires sequence data. Roseapetra farriae is found growing in the low intertidal zone on rocky reefs in shaded, understorey habitats.


2014 ◽  
Vol 27 (6) ◽  
pp. 355 ◽  
Author(s):  
Daniel J. Ohlsen ◽  
Leon R. Perrie ◽  
Lara D. Shepherd ◽  
Patrick J. Brownsey ◽  
Michael J. Bayly

Aspleniaceae is one of the largest fern families. It is species-rich in Australasia and the south-western Pacific (ASWP), where approximately 115 species occur. In the current study, the chloroplast regions rbcL, trnL–trnF and rps4–trnS were sequenced for 100 Aspleniaceae samples from ASWP. These data were combined with published sequences for species from New Zealand and other regions for phylogenetic analyses. Species of Aspleniaceae from ASWP were placed in six of the eight previously identified inter-continental clades. The majority of species from ASWP were placed in two of these clades, with the remaining four clades each being represented by three or fewer species. Strong biogeographic affinities with South-east Asia were observed and immigration, rather than local radiations of endemic taxa, appears to have made a more important contribution to patterns of diversity in ASWP. This study supports the current taxonomic practice of recognising two genera, Asplenium L. and Hymenasplenium Hayata, in Aspleniaceae, and identifies future taxonomic work required for the family in this region, including potential synonymising of species, and revision of species complexes or widespread species that are demonstrably non-monophyletic.


2020 ◽  
Vol 14 (1) ◽  

This study aims to assess the intraspecific genetic diversity of Ixora macrophylla, a widespread species of Philippine Ixora recorded from several islands of the Philippines, and I. auriculata, an endemic species that has yet to be included in molecular studies of the Philippine Ixora. The number of haplotypes, haplotype diversity, and nucleotide diversity of 19 trnL-F and 17 ITS sequences of I. macrophylla, as well as 4 trnL-F and 4 ITS sequences of I. auriculata were obtained using DNAsp 5.10.1 software, and pairwise distances were calculated using the nucleotide Kimura 2-parameter using MEGA 6.06. Two haplotypes of trnL-F and nine haplotypes of ITS were identified in six populations of I. macrophylla. One of the two haplotypes of trnL-F was unique to the Mindoro population. One of the nine haplotypes of ITS was common among seven individuals from four populations. Intraspecific pairwise distances ranged from 0 to 0.1% for trnL-F and 0 to 0.9% for ITS. Mantel test showed weak correlations between the genetic and geographic distances for both trnL-F (r = -0.0380) and ITS (r = 0.0980) sequences. For the genetic diversity of I. auriculata, two haplotypes of trnL-F and four haplotypes of ITS were identified, with intraspecific pairwise distances ranging from 0 to 0.1% in trnL-F and 0.3 to 3.5% in ITS. The results for genetic diversity may be used to better understand the population genetics of the Philippine Ixora and provide insights for conservation.


2021 ◽  
Author(s):  
◽  
Whitney L M Bouma

<p>The fern family Pteridaceae is among the largest fern families in New Zealand. It comprises 17 native species among five genera. Traditionally the classification of Pteridaceae was based on morphological characters. The advent of molecular technology, now makes is possible to test these morphology-based classifications. The Pteridaceae has previously been subjected to phylogenetic analyses; however representatives from New Zealand and the South Pacific have never been well represented in these studies. This thesis research aimed to investigate the phylogenetic relationships of the New Zealand Pteridaceae, as well as, the phylogenetic relationships of the New Zealand species to their overseas relatives. The DNA sequences of several Chloroplast loci (e.g. trnL-trnF locus, rps4 and rps4-trnS IGS, atpB, and rbcL) were determined and the phylogenetic relationships of the New Zealand Pteridaceae and several species-specific question within the genus Pellaea and Adiantum were investigated. Results presented in this thesis confirm previously published phylogenetics of the Pteridaceae, which show the resolution of five major clades, i.e.,cryptogrammoids, ceratopteridoids, pteridoids, cheilanthoids, and the adiantoids. The addition of the New Zealand species revealed a possible South West Pacific groups formed by the respective genera, where New Zealand species were generally more related to one another than to overseas relatives. Within the New Zealand Pellaea, the analysis of the trnL-trnF locus sequence data showed that the morphologically-intermediate plants P. aff. falcata, responsible for taxonomic confusion, were more closely related to P. rotundifolia than to P. falcata. Furthermore, the species collected on the Kermadec Islands, previously thought to be P. falcata, are genetically distinct from the Australian P. falcata and they could constitute a new species. Adiantum hispidulum, which is polymorphic for two different hair types being used to distinguish them as different species, was also reinvestigated morphologically and molecularly. Morphological inspection of hairs revealed three hair types as opposed to the previous thought two, and furthermore, they correspond to three different trnL-trnF sequences haplotypes.</p>


2008 ◽  
Vol 363 (1508) ◽  
pp. 3427-3437 ◽  
Author(s):  
Renae C Pratt ◽  
Mary Morgan-Richards ◽  
Steve A Trewick

New Zealand taxa from the Orthopteran family Anostostomatidae have been shown to consist of three broad groups, Hemiandrus (ground weta), Anisoura/Motuweta (tusked weta) and Hemideina – Deinacrida (tree–giant weta). The family is also present in Australia and New Caledonia, the nearest large land masses to New Zealand. All genera are endemic to their respective countries except Hemiandrus that occurs in New Zealand and Australia. We used nuclear and mitochondrial DNA sequence data to study within genera and among species-level genetic diversity within New Zealand and to examine phylogenetic relationships of taxa in Australasia. We found the Anostostomatidae to be monophyletic within Ensifera, and justifiably distinguished from the Stenopelmatidae among which they were formerly placed. However, the New Zealand Anostostomatidae are not monophyletic with respect to Australian and New Caledonian species in our analyses. Two of the New Zealand groups have closer allies in Australia and one in New Caledonia. We carried out maximum-likelihood and Bayesian analyses to reveal several well supported subgroupings. Our analysis included the most extensive sampling to date of Hemiandrus species and indicate that Australian and New Zealand Hemiandrus are not monophyletic. We used molecular dating approaches to test the plausibility of alternative biogeographic hypotheses for the origin of the New Zealand anostostomatid fauna and found support for divergence of the main clades at, or shortly after, Gondwanan break-up, and dispersal across the Tasman much more recently.


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