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Hoberg EP, Zarlenga DS. Evolution and Biogeography of Haemonchus contortus: Linking Faunal Dynamics in Space and Time. ADVANCES IN PARASITOLOGY 2017; 93:1-30. [PMID: 27238001 DOI: 10.1016/bs.apar.2016.02.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
History is the foundation that informs about the nuances of faunal assembly that are essential in understanding the dynamic nature of the host-parasite interface. All of our knowledge begins and ends with evolution, ecology and biogeography, as these interacting facets determine the history of biodiverse systems. These components, relating to Haemonchus, can inform about the complex history of geographical distribution, host association and the intricacies of host-parasite associations that are played out in physiological and behavioural processes that influence the potential for disease and our capacity for effective control in a rapidly changing world. Origins and evolutionary diversification among species of the genus Haemonchus and Haemonchus contortus occurred in a complex crucible defined by shifts in environmental structure emerging from cycles of climate change and ecological perturbation during the late Tertiary and through the Quaternary. A history of sequential host colonization associated with waves of dispersal bringing assemblages of ungulates from Eurasia into Africa and processes emerging from ecosystems in collision and faunal turnover defined the arena for radiation among 12 recognized species of Haemonchus. Among congeners, the host range for H. contortus is exceptionally broad, including species among artiodactyls of 40 genera representing 5 families (and within 12 tribes of Bovidae). Broad host range is dramatically reflected in the degree to which translocation, introduction and invasion with host switching, has characterized an expanding distribution over time in North America, South America, southern Eurasia, Australia and New Zealand, coincidental with agriculture, husbandry and global colonization by human populations driven particularly by European exploration after the 1500s. African origins in xeric to mesic habitats of the African savannah suggest that historical constraints linked to ecological adaptations (tolerances and developmental thresholds defined by temperature and humidity for larval stages) will be substantial determinants in the potential outcomes for widespread geographical and host colonization which are predicted to unfold over the coming century. Insights about deeper evolutionary events, ecology and biogeography are critical as understanding history informs us about the possible range of responses in complex systems under new regimes of environmental forcing, especially, in this case, ecological perturbation linked to climate change. A deeper history of perturbation is relevant in understanding contemporary systems that are now strongly structured by events of invasion and colonization. The relaxation of abiotic and biotic controls on the occurrence of H. contortus, coincidental with inception and dissemination of anthelmintic resistance may be synergistic, serving to exacerbate challenges to control parasites or to limit the socioeconomic impacts of infection that can influence food security and availability. Studies of haemonchine nematodes contribute directly to an expanding model about the nature of diversity and the evolutionary trajectories for faunal assembly among complex host-parasite systems across considerable spatial and temporal scales.
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Affiliation(s)
- E P Hoberg
- US National Parasite Collection and Animal Parasitic Disease Laboratory, Agricultural Research Service, USDA, Beltsville, MD, United States
| | - D S Zarlenga
- Animal Parasitic Disease Laboratory, Agricultural Research Service, USDA, Beltsville, MD, United States
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Gracianne C, Jan P, Fournet S, Olivier E, Arnaud J, Porte C, Bardou‐Valette S, Denis M, Petit EJ. Temporal sampling helps unravel the genetic structure of naturally occurring populations of a phytoparasitic nematode. 2. Separating the relative effects of gene flow and genetic drift. Evol Appl 2016; 9:1005-16. [PMID: 27606008 PMCID: PMC4999530 DOI: 10.1111/eva.12401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 06/06/2016] [Indexed: 11/29/2022] Open
Abstract
Studying wild pathogen populations in natural ecosystems offers the opportunity to better understand the evolutionary dynamics of biotic diseases in crops and to enhance pest control strategies. We used simulations and genetic markers to investigate the spatial and temporal population genetic structure of wild populations of the beet cyst nematode Heterodera schachtii on a wild host plant species, the sea beet (Beta vulgaris spp. maritima), the wild ancestor of cultivated beets. Our analysis of the variation of eight microsatellite loci across four study sites showed that (i) wild H. schachtii populations displayed fine-scaled genetic structure with no evidence of substantial levels of gene flow beyond the scale of the host plant, and comparisons with simulations indicated that (ii) genetic drift substantially affected the residual signals of isolation-by-distance processes, leading to departures from migration-drift equilibrium. In contrast to what can be suspected for (crop) field populations, this showed that wild cyst nematodes have very low dispersal capabilities and are strongly disconnected from each other. Our results provide some key elements for designing pest control strategies, such as decreasing passive dispersal events to limit the spread of virulence among field nematode populations.
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Affiliation(s)
- Cécile Gracianne
- IGEPPINRA, Agrocampus OuestUniversité Rennes 1Le RheuFrance
- VetAgro Sup, UMR 1095, GDECClermont UniversitéClermont‐FerrandFrance
| | - Pierre‐Loup Jan
- IGEPPINRA, Agrocampus OuestUniversité Rennes 1Le RheuFrance
- ESE, Ecology and Ecosystems HealthAgrocampus OuestINRARennesFrance
| | | | - Eric Olivier
- IGEPPINRA, Agrocampus OuestUniversité Rennes 1Le RheuFrance
| | - Jean‐François Arnaud
- UMR CNRS 8198 ÉvolutionÉcologie et PaléontologieUniversité Lille 1 ‐ Sciences et TechnologiesVilleneuve d'Ascq CedexFrance
| | | | | | | | - Eric J. Petit
- ESE, Ecology and Ecosystems HealthAgrocampus OuestINRARennesFrance
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Abstract
Haemonchus contortus is one of the most successful and problematic livestock parasites worldwide. From its apparent evolutionary origins in sub-Saharan Africa, it is now found in small ruminants in almost all regions of the globe, and can infect a range of different domestic and wildlife artiodactyl hosts. It has a remarkably high propensity to develop resistance to anthelmintic drugs, making control increasingly difficult. The success of this parasite is, at least in part, due to its extremely high levels of genetic diversity that, in turn, provide a high adaptive capacity. Understanding this genetic diversity is important for many areas of research including anthelmintic resistance, epidemiology, control, drug/vaccine development and molecular diagnostics. In this article, we review the current knowledge of H. contortus genetic diversity and population structure for both field isolates and laboratory strains. We highlight the practical relevance of this knowledge with a particular emphasis on anthelmintic resistance research.
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Ács Z, Hayward A, Sugár L. Genetic diversity and population genetics of large lungworms (Dictyocaulus, Nematoda) in wild deer in Hungary. Parasitol Res 2016; 115:3295-312. [PMID: 27150969 PMCID: PMC4980422 DOI: 10.1007/s00436-016-5088-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 04/21/2016] [Indexed: 11/29/2022]
Abstract
Dictyocaulus nematode worms live as parasites in the lower airways of ungulates and can cause significant disease in both wild and farmed hosts. This study represents the first population genetic analysis of large lungworms in wildlife. Specifically, we quantify genetic variation in Dictyocaulus lungworms from wild deer (red deer, fallow deer and roe deer) in Hungary, based on mitochondrial cytochrome c oxidase subunit 1 (cox1) sequence data, using population genetic and phylogenetic analyses. The studied Dictyocaulus taxa display considerable genetic diversity. At least one cryptic species and a new parasite–host relationship are revealed by our molecular study. Population genetic analyses for Dictyocaulus eckerti revealed high gene flow amongst weakly structured spatial populations that utilise the three host deer species considered here. Our results suggest that D. eckerti is a widespread generalist parasite in ungulates, with a diverse genetic backround and high evolutionary potential. In contrast, evidence of cryptic genetic structure at regional geographic scales was observed for Dictyocaulus capreolus, which infects just one host species, suggesting it is a specialist within the studied area. D. capreolus displayed lower genetic diversity overall, with only moderate gene flow compared to the closely related D. eckerti. We suggest that the differing vagility and dispersal behaviour of hosts are important contributing factors to the population structure of lungworms, and possibly other nematode parasites with single-host life cycles. Our findings are of relevance for the management of lungworms in deer farms and wild deer populations.
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Affiliation(s)
- Zoltán Ács
- Department of Wildlife Biology and Ethology, Faculty of Animal and Environmental Sciences, Kaposvar University, 7400, Kaposvár, Hungary
| | - Alexander Hayward
- Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn, TR10 9E2, UK.
| | - László Sugár
- Department of Wildlife Biology and Ethology, Faculty of Animal and Environmental Sciences, Kaposvar University, 7400, Kaposvár, Hungary
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Hotchen A, Chin K, Raja M. Nematode infection: A rare mimic of acute appendicitis. Int J Surg Case Rep 2014; 5:544-6. [PMID: 25024022 PMCID: PMC4147649 DOI: 10.1016/j.ijscr.2014.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2014] [Accepted: 05/14/2014] [Indexed: 10/25/2022] Open
Abstract
INTRODUCTION Acute appendicitis is a common condition seen in all surgical units. One rare condition that can mimic acute appendicitis is a nematode infection of the bowel. There have been few reported cases of nematode infection within the appendix and none that have been accompanied by intra-operative pictures. PRESENTATION OF CASE A 16-year-old female presented with a 12h history of right iliac fossa pain and mild pyrexia. Bloods showed a neutrophilia and normal C-reactive protein. Laparoscopy was performed which revealed a non-inflamed appendix. The appendix was dissected and a live nematode was visualised exiting the base of the appendix. Anti-helminthics were given and the infection resolved. DISCUSSION Nematode infection is most commonly seen in Africa, Asia and South America. When seen within the United Kingdom (UK), it is seen most commonly within high-risk populations. Testing for these infections is not routine within the UK and when they are performed, the results take a considerable amount of time to return. These tests should be considered within high-risk populations so that unnecessary surgery can be avoided. CONCLUSION This case highlights the importance of considering rare causes of right iliac fossa pain including nematode infection in a young patient. The case highlights this by giving intra-operative pictures of live nematodes upon dissection of the appendix.
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Affiliation(s)
- Andrew Hotchen
- Department of Surgery, Milton Keynes General Hospital, Milton Keynes MK65LD, UK.
| | - Kian Chin
- Department of Surgery, Milton Keynes General Hospital, Milton Keynes MK65LD, UK
| | - Mahzar Raja
- Department of Surgery, Milton Keynes General Hospital, Milton Keynes MK65LD, UK
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Gilabert A, Wasmuth JD. Unravelling parasitic nematode natural history using population genetics. Trends Parasitol 2013; 29:438-48. [PMID: 23948430 DOI: 10.1016/j.pt.2013.07.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/10/2013] [Accepted: 07/11/2013] [Indexed: 01/01/2023]
Abstract
The health and economic importance of parasitic nematodes cannot be overstated. Moreover, they offer a complex and diverse array of life strategies, raising a multitude of evolutionary questions. Researchers are applying population genetics to parasitic nematodes in order to disentangle some aspects of their life strategies, improve our knowledge about disease epidemiology, and design control strategies. However, population genetics studies of nematodes have been constrained due to the difficulty in sampling nematodes and developing molecular markers. In this context, new computational and sequencing technologies represent promising tools to investigate population genomics of parasitic, non-model, nematode species in an epidemiological context.
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Affiliation(s)
- Aude Gilabert
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, T2N 4Z6, Canada
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Archie EA, Ezenwa VO. Population genetic structure and history of a generalist parasite infecting multiple sympatric host species. Int J Parasitol 2011; 41:89-98. [DOI: 10.1016/j.ijpara.2010.07.014] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 07/17/2010] [Accepted: 07/26/2010] [Indexed: 11/24/2022]
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Barrett LG, Thrall PH, Burdon JJ, Linde CC. Life history determines genetic structure and evolutionary potential of host-parasite interactions. Trends Ecol Evol 2008; 23:678-85. [PMID: 18947899 DOI: 10.1016/j.tree.2008.06.017] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Revised: 06/25/2008] [Accepted: 06/26/2008] [Indexed: 02/04/2023]
Abstract
Measures of population genetic structure and diversity of disease-causing organisms are commonly used to draw inferences regarding their evolutionary history and potential to generate new variation in traits that determine interactions with their hosts. Parasite species exhibit a range of population structures and life-history strategies, including different transmission modes, life-cycle complexity, off-host survival mechanisms and dispersal ability. These are important determinants of the frequency and predictability of interactions with host species. Yet the complex causal relationships between spatial structure, life history and the evolutionary dynamics of parasite populations are not well understood. We demonstrate that a clear picture of the evolutionary potential of parasitic organisms and their demographic and evolutionary histories can only come from understanding the role of life history and spatial structure in influencing population dynamics and epidemiological patterns.
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Affiliation(s)
- Luke G Barrett
- CSIRO Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia.
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Rosenthal BM, Dunams DB, Pritt B. Restricted genetic diversity in the ubiquitous cattle parasite, Sarcocystis cruzi. INFECTION GENETICS AND EVOLUTION 2008; 8:588-92. [DOI: 10.1016/j.meegid.2008.04.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 04/09/2008] [Accepted: 04/11/2008] [Indexed: 11/16/2022]
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Webster LMI, Johnson PCD, Adam A, Mable BK, Keller LF. Macrogeographic population structure in a parasitic nematode with avian hosts. Vet Parasitol 2007; 144:93-103. [PMID: 17097808 DOI: 10.1016/j.vetpar.2006.09.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Revised: 09/08/2006] [Accepted: 09/13/2006] [Indexed: 12/01/2022]
Abstract
Much remains to be discovered about the population genetic structure of parasites, despite the importance of such knowledge to understanding the processes involved in the spread of drug resistance through populations. Here we present a study of population genetic diversity in Trichostrongylus tenuis, an avian parasitic nematode infecting both poultry and game birds, where anthelmintic use is common. We examined diversity of nicotinamide dehydrogenase subunit 4 (nad4) mtDNA sequences within and between seven locations: five in the UK (red grouse hosts), one in Iceland (domestic goose) and one in Norway (willow grouse). Within-UK comparisons showed high nucleotide diversity (pi=0.015, n=23) but no structure between locations (Phi(ST)=0.022, P=0.27), with over 97% of variation distributed within-hosts. The highest diversity was found in Iceland (pi=0.043, n=4), and the lowest in Norway (pi=0.003, n=4). Differentiation between countries was considerable (Phi(CT)=0.44, P<0.05), in spite of the potential mixing effects of gene flow via migrating wild hosts and the poultry trade. However, significant pairwise F(ST) values were found only between Norway and the other locations. Phylogenetic analysis provided statistical support for a separate clade for Norwegian samples only, with unresolved diversity leading to a star-shaped relationship between Icelandic and UK haplotypes. These results suggest that Norwegian T. tenuis are isolated, but that there is some connectivity between UK and Icelandic populations. Although anthelmintic resistance has not yet been reported for T. tenuis, the population structure is such that emerging resistance has the potential to spread by gene flow over a large geographic scale.
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Affiliation(s)
- Lucy M I Webster
- Division of Environmental and Evolutionary Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK.
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Troell K, Engström A, Morrison DA, Mattsson JG, Höglund J. Global patterns reveal strong population structure in Haemonchus contortus, a nematode parasite of domesticated ruminants. Int J Parasitol 2006; 36:1305-16. [PMID: 16950266 DOI: 10.1016/j.ijpara.2006.06.015] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Revised: 05/09/2006] [Accepted: 06/27/2006] [Indexed: 10/24/2022]
Abstract
We have examined the global population genetic structure of Haemonchus contortus. The genetic variability was studied using both amplified fragment length polymorphism (AFLP) and nad4 sequences of the mitochondrial genome. To examine the performance and information content of the two different marker systems, comparative assessment of population genetic diversity was undertaken in 19 isolates of H. contortus, a parasitic nematode of small ruminants. A total of 150 individual adult worms representing 14 countries from all inhabited continents were analysed. Altogether 1,429 informative AFLP markers were generated using four different primer combinations. Also, the genetic variation was high, which agrees with results from previous AFLP studies of nematode parasites of livestock. The genetic structure was high, indicating limited gene flow between the different isolates and populations from each continent mostly formed monophyletic groups in the phylogenetic analysis. However, for isolates representing Australia, Greece and one laboratory strain that originated from South Africa (WRS), there was no clear genetic relationship between the isolates and the distance between their geographical origins. Basically the same pattern was observed for the mitochondrial marker, although the phylogenetic analysis was less resolved than for AFLP. In contrast with previous findings on the population genetic structure of H. contortus, the calculation of population structure gave high values (Nst=0.59). The strong structure was present also for the four Swedish isolates (Nst=0.16) representing a small geographical area.
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Affiliation(s)
- Karin Troell
- Department of Parasitology (SWEPAR), National Veterinary Institute and Swedish University of Agricultural Sciences, 751 89 Uppsala, Sweden
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Höglund J, Morrison DA, Mattsson JG, Engström A. Population genetics of the bovine/cattle lungworm (Dictyocaulus viviparus) based on mtDNA and AFLP marker techniques. Parasitology 2006; 133:89-99. [PMID: 16515731 DOI: 10.1017/s0031182006009991] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 01/20/2006] [Accepted: 01/21/2006] [Indexed: 11/06/2022]
Abstract
Mitochondrial DNA (mtDNA) sequence data and amplified fragment length polymorphism (AFLP) patterns were compared for the lungworm Dictyocaulus viviparus, a nematode parasite of cattle. Eight individual D. viviparus samples from each of 8 herds in Sweden and 1 laboratory isolate were analysed, with the aim of describing the diversity and genetic structure in populations using different genetic markers on exactly the same DNA samples. There was qualitative agreement between the whole-genome AFLP data and the mtDNA sequence data, both indicating relatively strong genetic differentiation among the Swedish farms. However, the AFLP data detected much more genetic variation than did the mtDNA data, even after allowing for the different inheritance patterns of the markers, and indicated that there was much less differentiation among the populations. The mtDNA data therefore seemed to be more informative about the most recent history of the parasite populations, as the general patterns were less obscured by detailed inter-relationships among individual worms. The 4 mtDNA genes sequenced (1542 bp) showed consistent patterns, although there was more genetic variation in the protein-coding genes than in the structural RNA genes. Furthermore, there appeared to be at least 3 distinct genetic groups of D. viviparus infecting Swedish cattle, 1 of which was predominant and showed considerable differentiation between farms, but not necessarily within farms. Second, the 2 smaller genetic groups occurred on farms where the predominant group also occurred, suggesting that these farms have had multiple introductions of D. viviparus.
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Affiliation(s)
- J Höglund
- Department of Parasitology (SWEPAR), National Veterinary Institute and Swedish University of Agricultural Sciences, 751 89 Uppsala, Sweden.
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Hypsa V. Parasite histories and novel phylogenetic tools: Alternative approaches to inferring parasite evolution from molecular markers. Int J Parasitol 2006; 36:141-55. [PMID: 16387305 DOI: 10.1016/j.ijpara.2005.10.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Revised: 10/19/2005] [Accepted: 10/28/2005] [Indexed: 10/25/2022]
Abstract
Parasitological research is often contingent on the knowledge of the phylogeny/genealogy of the studied group. Although molecular phylogenetics has proved to be a powerful tool in such investigations, its application in the traditional fashion, based on a tree inference from the primary nucleotide sequences may, in many cases, be insufficient or even improper. These limitations are due to a number of factors, such as a scarcity/ambiguity of phylogenetic information in the sequences, an intricacy of gene relationships at low phylogenetic levels, or a lack of criteria when deciding among several competing coevolutionary scenarios. With respect to the importance of a precise and reliable phylogenetic background in many biological studies, attempts are being made to extend molecular phylogenetics with a variety of new data sources and methodologies. In this review, selected approaches potentially applicable to parasitological research are presented and their advantages as well as drawbacks are discussed. These issues include the usage of idiosyncratic markers (unique features with presumably low probability of homoplasy), such as insertion of mobile elements, gene rearrangements and secondary structure features; the problem of ancestral polymorphism and reticulate relationships at low phylogenetic levels; and the utility of a molecular clock to facilitate discrimination among alternative scenarios in host-parasite coevolution.
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Affiliation(s)
- Václav Hypsa
- Faculty of Biological Sciences, University of South Bohemia, and Institute of Parasitology, Academy of Sciences of the Czech Republic, Branisovská 31, 37005 Ceské Budejovice, Czech Republic.
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