Hostname: page-component-76fb5796d-r6qrq Total loading time: 0 Render date: 2024-04-27T01:08:47.269Z Has data issue: false hasContentIssue false
  • English
  • Français

Do molecules matter more than morphology? Promises and pitfalls in parasites

Published online by Cambridge University Press:  09 June 2011

S. L. PERKINS ,
E. S. MARTINSEN  and
B. G. FALK
S. L. PERKINS*
Affiliation:
Sackler Institute for Comparative Genomics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA
E. S. MARTINSEN
Affiliation:
Smithsonian Conservation Biology Institute, National Zoological Park, Washington, D.C. 20008, USA
B. G. FALK
Affiliation:
Sackler Institute for Comparative Genomics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA Richard Gilder Graduate School, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA
*
*Corresponding Author: Tel: 01-212-313-7646 Fax: 01-212-313-7819. E-mail: perkins@amnh.org
Get access Rights & Permissions [Opens in a new window]

Summary

Systematics involves resolving both the taxonomy and phylogenetic placement of organisms. We review the advantages and disadvantages of the two kinds of information commonly used for such inferences – morphological and molecular data – as applied to the systematics of metazoan parasites generally, with special attention to the malaria parasites. The problems that potentially confound the use of morphology in parasites include challenges to consistent specimen preservation, plasticity of features depending on hosts or other environmental factors, and morphological convergence. Molecular characters such as DNA sequences present an alternative data source and are particularly useful when not all the parasite's life stages are present or when parasitaemia is low. Nonetheless, molecular data can bring challenges that include troublesome DNA isolation, paralogous gene copies, difficulty in developing molecular markers, and preferential amplification in mixed species infections. Given the differential benefits and shortcomings of both molecular and morphological characters, both should be implemented in parasite taxonomy and phylogenetics.

Keywords

Integrated taxonomymolecular systematicscryptic species
Type
Research Article
Information
Parasitology , Volume 138 , Special Issue 13: Systematics as a cornerstone of parasitology , November 2011 , pp. 1664 - 1674
Copyright
Copyright © Cambridge University Press 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Agustí, C., Aznar, F. J., Oldon, P. D., Littlewood, D. T. J., Kostadinova, A. and Raga, J. A. (2005). Morphological and molecular characterization of tetraphyllidean merocercoids (Platyhelminthes: Cestoda) of striped dolphins (Stenella coeruleoalba) from the Western Mediterranean. Parasitology 130, 461–474.CrossRefGoogle ScholarPubMed
Aviles, H., Belli, A., Armijos, R., Monroy, F. P. and Harris, E. (1999) PCR detection and identification of Leishmania parasites in clinical specimens in Ecuador: a comparison with classical diagnostic methods. Journal of Parasitology 85, 181–187.CrossRefGoogle ScholarPubMed
Barnard, W. H. and Bair, R. D. (1986). Prevalence of avian hematozoa in central Vermont. Journal of Wildlife Diseases 22, 365–374.CrossRefGoogle ScholarPubMed
Beadell, J. S., Ishtiaq, F., Covas, R., Melo, M., Warren, B. H., Atkinson, C. T., Bensch, S., Graves, G. R., Jhala, Y. V., Peirce, M. A., Rahmani, A. R., Fonseca, D. M. and Fleischer, R. C. (2006). Global phylogeographic limits of Hawaii's avian malaria. Proceedings of the Royal Society B 273, 2935–2944.CrossRefGoogle ScholarPubMed
Bensch, S., Stjernman, M., Hasselquist, D., Ostman, O., Hansson, B., Westerdahl, H. and Pinheiro, R. T. (2000). Host specificity in avian blood parasites: a study of Plasmodium and Haemoproteus mitochondrial DNA amplified from birds. Proceedings of the Royal Society B 267, 1583–1589.CrossRefGoogle ScholarPubMed
Bezzhonova, O. V. and Goryacheva, I. I. (2008). Intragenomic heterogeneity of rDNA internal transcribed spacer 2 in Anopheles messeae (Diptera:Culicidae). Journal of Medical Entomology 45, 337–341.CrossRefGoogle ScholarPubMed
Blasco-Costa, I., Balbuena, J. A., Raga, J. A., Kostadinova, A. and Olson, P. D. (2010). Molecules and morphology reveal cryptic variation among digeneans infecting sympatric mullets in the Mediterranean. Parasitology 137, 287–302.CrossRefGoogle ScholarPubMed
Brant, S. V. and Orti, G. (2003). Evidence for gene flow in parasitic nematodes between two host species of shrews. Molecular Ecology 12, 2853–2859.CrossRefGoogle ScholarPubMed
Brooks, D. R. (1979). Testing hypotheses of evolutionary relationships among parasites: the digeneans of crocodiles. American Zoologist 19, 1225–1238.CrossRefGoogle Scholar
Brooks, D. R. and Hoberg, E. P. (2001). Parasite systematics in the 21st century: opportunities and obstacles. Trends in Parasitology 17, 273–275.CrossRefGoogle ScholarPubMed
Bruce, J. I., Llewellyn, L. M. and Sadun, E. H. (1961). Susceptibility of wild mammals to infection by Schistosoma mansoni. Journal of Parasitology 47, 752–756.CrossRefGoogle ScholarPubMed
Bullock, W. L. (1969) Morphological features as tools and as pitfalls in acanthocephalan systematics. In Problems in Systematics of Parasites (ed. Schmidt, G. D.), pp. 9–45. University Park Press, Baltimore, USA.Google Scholar
Campos, A., Cummings, M. P., Reyes, J. L. and Laclette, J. P. (1998). Phylogenetic relationships of platyhelminthes based on 18S ribosomal gene sequences. Molecular Phylogenetics and Evolution 10, 1–10.CrossRefGoogle ScholarPubMed
Carmichael, A. C. (1984). Phylogeny and historical biogeography of the Schistosomatidae. Ph.D. thesis, Michigan State University, Michigan.Google Scholar
Cribb, T. H. and Bray, R. S. (2010). Gut wash, body soak, blender and heat-fixation: approaches to the effective collection, fixation and preservation of trematodes of fishes. Systematic Parasitology 76, 1–7.CrossRefGoogle Scholar
Criscione, C. D. and Font, W. F. (2001). Artifactual and natural variation of Oochoristica javaensis: statistical evaluation of in situ fixation. Comparative Parasitology 68, 156–163.Google Scholar
Crites, J. L. (1962). Morphology as a basis of identification and classification of parasites. Journal of Parasitology 48, 652–655.CrossRefGoogle ScholarPubMed
de León, G. P. P. and Nadler, S. A. (2010). What we don't recognize can hurt us: a plea for awareness about cryptic species. Journal of Parasitology 96, 453–464.CrossRefGoogle Scholar
Dmitrieva, E. and Dimitrov, G. (2002). Variability in the taxonomic characters of Black Sea gyrodactylids (Monogenea). Systematic Parasitology 51, 199–206.CrossRefGoogle ScholarPubMed
Dolnik, O. V., Palinauskas, V. and Bensch, S. (2009). Individual oocysts of Isospora (Apicomplexa: Coccidia) parasites from avian feces: from photo to sequence. Journal of Parasitology 95, 169–174.CrossRefGoogle ScholarPubMed
Donald, K. M., Kennedy, M., Poulin, R. and Spencer, H. G. (2004). Host specificity and molecular phylogeny of larval Digenea isolated from New Zealand and Australian topshells (Gastropoda: Trochidae). International Journal for Parasitology 34, 557–568.CrossRefGoogle ScholarPubMed
Escalante, A. A. and Ayala, F. J. (1994). Phylogeny of the malarial genus Plasmodium, derived from rRNA gene sequences. Proceedings of the National Academy of Sciences, USA 91, 11373–11377.CrossRefGoogle ScholarPubMed
Escalante, A. A., Freeland, D. E., Collins, W. E. and Lal, A. A. (1998). The evolution of primate malaria parasites based on the gene encoding cytochrome b from the linear mitochondrial genome. Proceedings of the National Academy of Sciences, USA 95, 8124–8129.CrossRefGoogle ScholarPubMed
Eszterbauer, E. (2004). Genetic relationship among gill-infecting Myxobolus species (Myxosporea) of cyprinids: molecular evidence of importance of tissue-specificity. Diseases of Aquatic Organisms 58, 35–40.CrossRefGoogle ScholarPubMed
Evans, N. M., Holder, M. T., Barbeitos, M. S., Okamura, B. and Cartwright, P. (2010). The phylogenetic position of Myxozoa” exploring conflicting signals in phylogenomic and ribosomal data sets. Molecular Biology and Evolution 27, 2733–2746.CrossRefGoogle ScholarPubMed
Fallon, S. M. and Ricklefs, R. E. (2008). Parasitemia in PCR-detected Plasmodium and Haemoproteus infections in birds. Journal of Avian Biology 39, 514–522.CrossRefGoogle Scholar
Ferri, E., Barbuto, M., Bain, O., Galimberti, A., Uni, S., Guerrero, R., Ferté, H., Bandi, C., Martin, C. and Casiraghi, M. (2009). Integrated taxonomy: traditional approach and DNA barcoding for the identification of filarioid worms and related parasites (Nematoda). Frontiers in Zoology 6, 1–12.CrossRefGoogle ScholarPubMed
Folmer, O., Black, M., Hoeh, W., Lutz, R. and Vrijenhoek, R. (1994). DNA primers for amplification of mitochondrial cytochrome c oxidase subunit I from diverse metazoan invertebrates. Molecular Marine Biology and Biotechnology 3, 294–299.Google ScholarPubMed
Funk, D. J. and Omland, K. E. (2003). Species–level paraphyly and polyphyly: frequency, causes and consequences, with insights from animal mitochondrial DNA. Annual Review of Ecology, Evolution, and Systematics 34, 397–423.CrossRefGoogle Scholar
Gilbert, M. T. P., Moore, W., Melchior, L. and Worobey, M. (2007). DNA extraction from dry museum beetles without conferring external morphological damage. PLoS One 2, e272. doi:10.1371/journal.pone.0000272.CrossRefGoogle ScholarPubMed
Gondim, L. F. P., Laski, P., Gao, L. and McAllister, M. M. (2004). Variation of the internal transcribed spacer 1 sequence within individual strains and among different strains of Neospora caninum. Journal of Parasitology 90, 119–122.CrossRefGoogle ScholarPubMed
Haley, A. J. (1962). Role of host relationships in the systematics of helminth parasites. Journal of Parasitology 48, 671–678.CrossRefGoogle Scholar
Hayward, A. (2010). Cryptic diversity and patterns of host specificity in trematode flatworms. Molecular Ecology 19, 2602–2604.CrossRefGoogle ScholarPubMed
Hikosaka, K., Watanabe, Y., Tsuji, N., Kita, K., Kishine, H., Arisue, N., Palacpac, N. M., Kawazu, S., Sawai, H., Horii, T., Igarashi, I. and Tanabe, K. (2010). Divergence of the mitochondrial genome structure of the apicomplexan parasites, Babesia and Theileria. Molecular Biology and Evolution 27, 1107–1116.CrossRefGoogle ScholarPubMed
Hillis, D. (1987). Molecular versus morphological approaches to systematics. Annual Review of Ecology and Systematics 18, 23–42.CrossRefGoogle Scholar
Hobbs, R. P. A., Lymbery, J. and Thompson, R. C. A. (1990). Rostellar hook characters of Echinococcus granulosus (Batsch, 1786) from natural and experimental Australian hosts, and its implication for strain recognition. Parasitology 101, 273–281.CrossRefGoogle ScholarPubMed
Hoberg, E. P., Mariaux, J., Justine, J.-L., Brooks, D. R. and Weekes, P. J. (1997). Phylogeny of the orders of the Eucestoda (Cercomeromorphae) based on comparative morphology: historical perspectives and a new working hypothesis. Journal of Parasitology 83, 1128–1147.CrossRefGoogle Scholar
Hu, M., Gasser, R. B., Chilton, N. B. and Beveridge, I. (2005). Genetic variation in the mitochondrial cytochrome c oxidase subunit 1 within three species of Progamotaenia (Cestoda: Anoplocephalidae) from macropodid marsupials. Parasitology 130, 117–129.CrossRefGoogle ScholarPubMed
Jenner, R. A. (2004). Accepting partnership by submission? Morphological phylogenetics in a molecular millennium. Systematic Biology 53, 333–342.CrossRefGoogle Scholar
Jordan, H. B. (1975). The effect of host constitution on the development of Plasmodium floridense. Journal of Protozoology 22, 241–244.CrossRefGoogle Scholar
Jordan, H. B. and Friend, M. B. (1971). The occurrence of Shellackia and Plasmodium in two Georgia lizards. Journal of Eukaryotic Microbiology 18, 485–487.Google ScholarPubMed
Ketmaier, V., Joyce, D. A., Horton, T. and Mariani, S. (2007). A molecular phylogenetic framework for the evolution of parasitic strategies in cymothoid isopods (Crustacea). Journal of Zoological Systematics and Evolutionary Research 46, 19–23.Google Scholar
Kralova-Hromadova, I., Stefka, J., Spakulova, M., Orosova, M., Bombarova, M., Hanzelova, V., Bazsalovicsova, E. and Scholz, T. (2010). Intra-individual internal transcribed spacer 1 (ITS1) and ITS2 ribosomal sequence variation linked with multiple rDNA loci: a case of triploid Atractolytocestus huronensis, the monozoic cestode of common carp. International Journal for Parasitology 40, 175–181.CrossRefGoogle ScholarPubMed
Lavikainen, A., Haukisalmi, V., Lehtinen, M. J., Henttonen, H., Oksanen, A. and Meri, S. (2008). A phylogeny of members of the family Taeniidae based on the mitochondrial cox1 and nad1 gene data. Parasitology 135, 1457–1467.CrossRefGoogle ScholarPubMed
Leo, N. P. and Barker, S. C. (2002). Intragenomic variation in ITS2 rDNA in the louse of humans, Pediculus humanus: ITS2 is not a suitable marker for population studies in this species. Insect Molecular Biology 11, 651–657.CrossRefGoogle Scholar
Leung, T. L. F., Keeney, D. B. and Poulin, R. (2009). Cryptic species complexes in manipulative echinostomatid trematodes: when two become six. Parasitology 136, 241–252.CrossRefGoogle ScholarPubMed
Li, A. X., DíAmelio, S., Paggi, L., He, F., Gasser, R. B., Lun, Z. R., Abollo, E., Turchetto, M. and Zhu, X. Q. (2005). Genetic evidence for the existence of sibling species within Contracaecum rudolphii (Hartwich, 1964) and the validity of Contracaecum septentrionale (Kreis, 1955) (Nematoda: Anisakidae). Parasitology Research 96, 361–366.CrossRefGoogle ScholarPubMed
Locke, S. A., McLaughlin, J. D. and Marcogliese, D. J. (2010). DNA barcodes show cryptic diversity and a potential physiological basis for host specificity among Diplostomoidea (Platyhelminthes: Digenea) parasitizing freshwater fishes in the St. Lawrence River, Canada. Molecular Ecology 19, 2813–2827.CrossRefGoogle Scholar
Maddison, W. P. (1997). Gene trees in species trees. Systematic Biology 46, 523–536.CrossRefGoogle Scholar
Mardis, E. R. (2008). The impact of next-generation sequencing technology on genetics. Trends in Genetics 24, 133–141.CrossRefGoogle ScholarPubMed
Mariaux, J. (1996). Cestode systematics: any progress? International Journal for Parasitology 26, 231–243.CrossRefGoogle ScholarPubMed
Mariaux, J. (1998). A molecular phylogeny of the Eucestoda. Journal of Parasitology 84, 114–124.CrossRefGoogle ScholarPubMed
Marques, J. F., Santos, M. J., Gibson, D. I., Cabral, H. N. and Olson, P. D. (2007). Cryptic species of Didymobothrium rudolphii (Cestoda: Spathebothriidae) from the sand sole, Solea lascaris, off the Portuguese coast, with an analysis of their molecules, morphology, ultrastructure and phylogeny. Parasitology 134, 1057–1072.CrossRefGoogle ScholarPubMed
Martínez-Aquino, A., Reyna-Fabián, M. E., Rosas-Valdez, R., Razo-Mendivil, U., Pérez-Ponce de León, G. and García-Varela, M. (2009). Detecting a complex of cryptic species within Neoechinorhynchus golvani (Acanthocephala: Neoechinirhynchidae) inferred from LSU rDNA sequences. Journal of Parasitology 95, 1040–1047.CrossRefGoogle Scholar
Martinsen, E. S., Paperna, I. and Schall, J. J. (2006). Morphological versus molecular identification of avian Haemosporidia: an exploration of three species concepts. Parasitology 133, 279–288.CrossRefGoogle ScholarPubMed
Martinsen, E. S., Perkins, S. L. and Schall, J. J. (2008). A three-genome phylogeny of malaria parasites. Molecular Phylogenetics and Evolution 47, 261–273.CrossRefGoogle ScholarPubMed
Mattingly, P. F. (1983). The paleogeography of mosquito-borne disease. Biological Journal of the Linnean Society 19, 185–210.CrossRefGoogle Scholar
McManus, D. P. and Bowles, J. (1996). Molecular genetic approaches to parasite identification: their value in diagnostic parasitology and systematics. International Journal for Parasitology 26, 687–704.CrossRefGoogle ScholarPubMed
Monis, P. T. (1999). The importance of systematics in parasitological research. International Journal for Parasitology 29, 381–388.CrossRefGoogle ScholarPubMed
Morand, S. and Müller-Graf, C. D. M. (2000). Muscles or testes? Comparative evidence for sexual competition among dioecious blood parasites (Schistosomatidae) of vertebrates. Parasitology 120, 45–56.CrossRefGoogle ScholarPubMed
Morrison, D. A. and Ellis, J. T. (1997). Effects of nucleotide sequence alignment on phylogeny estimation: a case study of 18S rDNAs of apicomplexa. Molecular Biology and Evolution 14, 428–441.CrossRefGoogle ScholarPubMed
Moszczynska, A., Locke, S. A., McLaughlin, J. D., Marcogliese, D. J. and Crease, T. J. (2009). Development of primers for the mitochondrial cytochrome c oxidase I gene in digenetic trematodes (Platyhelminthes) illustrates the challenge of barcoding parasitic helminths. Molecular Ecology Resources 9, 75–82.CrossRefGoogle ScholarPubMed
Naem, S., Pagan, C. and Nadler, S. A. (2010). Structural restoration of nematodes and acanthocephalans fixed in high percentage alcohol using DESS solution and rehydration. Journal of Parasitology 96, 809–811.CrossRefGoogle ScholarPubMed
Palinauskas, O. V., Dolnik, O. V., Valkiunas, G. and Bensch, S. (2009). Laser microdissection, microscopy, and single cell PCR of avian haemosporidians. Journal of Parasitology 96, 420–424.CrossRefGoogle Scholar
Perkins, S. L. (2000). Species concepts and malaria parasites: detecting a cryptic species of Plasmodium. Proceedings of the Royal Society of London B 267, 2345–2350.CrossRefGoogle ScholarPubMed
Perkins, S. L. (2008). Molecular systematics of the three mitochondrial protein-coding genes of malaria parasites: corroborative and new evidence for the origins of human malaria. Mitochondrial DNA 19, 471–478.Google ScholarPubMed
Perkins, S. L. and Austin, C. C. (2009). Four new species of Plasmodium from New Guinea lizards: integrating morphology and molecules. Journal of Parasitology 95, 424–433.CrossRefGoogle ScholarPubMed
Perkins, S. L., Osgood, S. M. and Schall, J. J. (1998) Use of PCR for detection of subpatent infections of lizard malaria: implications for epizootiology. Molecular Ecology 7, 1587–1590.CrossRefGoogle Scholar
Perkins, S. L. and Schall, J. J. (2002). A molecular phylogeny of malarial parasites recovered from cytochrome b gene sequences. Journal of Parasitology 88, 972–978.CrossRefGoogle ScholarPubMed
Poulin, R. (2007). Evolutionary Ecology of Parasites. Princeton: Princeton University Press.CrossRefGoogle Scholar
Poulin, R. (2011 a). Uneven distribution of cryptic diversity among higher taxa of parasitic worms. Biology Letters 7, 241–244. doi: 10.1098/rsbl.2010.0640.CrossRefGoogle ScholarPubMed
Poulin, R. (2011 b). The many roads to parasitism. A tale of convergence. Advances in Parasitology 74, 1–40.CrossRefGoogle ScholarPubMed
Qari, S. H., Shi, Y. P., Pieniazek, N. J., Collins, W. E. and Lal, A. A. (1996). Phylogenetic relationship among the malaria parasites based on small subunit rRNA gene sequences: monophyletic nature of the human malaria parasite, Plasmodium falciparum. Molecular Phylogenetics and Evolution 6, 157–165.CrossRefGoogle ScholarPubMed
Quicke, D. L. J. and Belshaw, R. (1999). Incongruence between morphological data sets: an example from the evolution of endoparasitism among parasitic wasps (Hymenoptera: Braconidae). Systematic Biology 48, 436–454.CrossRefGoogle Scholar
Read, C. P. and Rothman, A. H. (1957). The role of carbohydrates in the biology of cestodes. I. The effect of dietary carbohydrate quality on the size of Hymenolepis diminuta. Experimental Parasitology 6, 1–7.CrossRefGoogle ScholarPubMed
Refardt, D. and Ebert, D. (2006). Quantitative PCR to detect, discriminate and quantify intracellular parasites in their host: an example from three microsporidians in Daphnia. Parasitology 133, 11–18.CrossRefGoogle ScholarPubMed
Rich, S. M., Rosenthal, B. M. and Telford, S. R. III (1997). Heterogeneity of the internal transcribed spacer (ITS-2) region within individual deer ticks. Insect Molecular Biology 6, 123–129.CrossRefGoogle ScholarPubMed
Richard, F. A., Sehgal, R. N. M., Jones, H. I. and Smith, T. B. (2002). A comparative analysis of PCR-based detection methods for avian malaria. Journal of Parasitology 88, 819–822.CrossRefGoogle ScholarPubMed
Ricklefs, R. E. and Fallon, S. M. (2002). Diversification and host switching in avian malaria parasites. Proceedings of the Royal Society of London B 269, 885–892.CrossRefGoogle ScholarPubMed
Rogers, M. J., McConkey, G. A., Li, J. and McCutchan, T. F. (1995). The ribosomal DNA loci in Plasmodium falciparum accumulate mutations independently. Journal of Molecular Biology 254, 881–91.CrossRefGoogle ScholarPubMed
Schall, J. J. (1996). Malaria parasites of lizards: diversity and ecology. Advances in Parasitology 37, 255–333.CrossRefGoogle ScholarPubMed
Schmidt, G. D. (ed.) (1969). Problems in Systematics of Parasites. 131pp. University Park Press, Baltimore, USA.Google Scholar
Scotland, R. W., Olmstead, R. G. and Bennett, J. R. (2003). Phylogeny reconstruction: the role of morphology. Systematic Biology 52, 539–548.CrossRefGoogle ScholarPubMed
Sehgal, R. N. M., Jones, H. I. and Smith, T. B. (2001). Host specificity and incidence of Trypanosoma in some African rainforest birds: a molecular approach. Molecular Ecology 10, 2319–2327.CrossRefGoogle ScholarPubMed
Simon, C., Buckley, T. R., Frati, F., Stewart, J. B. and Beckenbach, A. T. (2006). Incorporating molecular evolution into phylogenetic analysis, and a new compilation of conserved polymerase chain reaction primers for animal mitochondrial DNA. Annual Review of Ecology, Evolution, and Systematics 37, 545–579.CrossRefGoogle Scholar
Simon, C., Frati, F., Beckenbach, A., Crespi, B., Liu, H. and Flook, P. (1994). Evolution, weighting, and phylogenetic utility of mitochondrial gene sequences and a compilation of conserved polymerase chain reaction primers. Annals of the Entomological Society of America 87, 651–701.CrossRefGoogle Scholar
Steinauer, M. L., Nickol, B. B. and Ortí, G. (2007). Cryptic speciation and patterns of phenotypic variation of a highly variable acanthocephalan parasite. Molecular Ecology 16, 4097–4109.CrossRefGoogle ScholarPubMed
Szöllsi, E., Hellgren, O. and Hasselquist, D. (2008). A cautionary note on the use of nested PCR for parasite screening: an example from avian blood parasites. Journal of Parasitology 94, 562–564.CrossRefGoogle ScholarPubMed
Valkiūnas, G. (2005). Avian Malaria Parasites and Other Haemosporidia. CRC Press.Google Scholar
Valkiunas, G., Bensch, S., Iezhova, T. A., Križanauskienė, A., Hellgren, O. and Bolshakov, C. V. (2006). Nested cytochrome B polymerase chain reaction diagnostics underestimate mixed infections of avian blood haemosporidian parasites: microscopy is still essential. Journal of Parasitology 92, 418–422.CrossRefGoogle ScholarPubMed
Valkiunas, G., Iezhova, T. A., Križanauskienė, A., Pallinauskas, V., Sehgal, R. N. M. and Bensch, S. (2008) A comparative analysis of microscopy and PCR-based detection methods for blood parasites. Journal of Parasitology 94, 1395–1401.CrossRefGoogle ScholarPubMed
Valkiūnas, G., Bensch, S., Iezhova, T. A., Križanauskienė, A., Hellgren, O. and Bolshakov, C. V. (2009) Nested cytochrome b polymerase chain reaction diagnostics detect sporozoites of hemosporidian parasites in peripheral blood of naturally infected birds. Journal of Parasitology 95, 1512–1515.CrossRefGoogle ScholarPubMed
Van Herwerden, L., Blair, D. and Agatsuma, T. (1998). Intra- and interspecific variation in nuclear ribosomal internal transcribed spacer 1 of the Schistosoma japonicum species complex. Parasitology 116, 311–317.CrossRefGoogle ScholarPubMed
Voge, M. (1969). Systematics of cestodes, present and future. In Problems in Systematics of Parasites (ed. Schmidt, G. D.), pp. 49–72. University Park Press, Baltimore.Google Scholar
Wang, D. and Bodovitz, S. (2010). Single cell analysis: the next frontier in ‘omics’. Trends in Biotechnology 28, 281–290.CrossRefGoogle Scholar
Waters, A. P., Higgins, D. G. and McCutchan, T. F. (1991). Plasmodium falciparum appears to have arisen as a result of lateral transfer between avian and human hosts. Proceedings of the National Academy of Sciences, USA 88, 3140–3144.CrossRefGoogle ScholarPubMed
Whitehead, P. (1990). Systematics: an endangered species. Systematic Zoology 39, 179–184.CrossRefGoogle Scholar
Wiens, J. J. (2004). The role of morphological data in phylogeny reconstruction. Systematic Biology 53, 653–661.CrossRefGoogle ScholarPubMed
Wiens, J. J., Chippendale, P. T. and Hillis, D. M. (2003). When are phylogenetic analyses misled by convergence? A case study in Texas cave salamanders. Systematic Biology 52, 501–514.CrossRefGoogle ScholarPubMed
Wiens, J. J. and Penkrot, T. L. (2002). Delimiting species based on DNA and morphological variation and discordant species limits in spiny lizards (Sceloporus). Systematic Biology 51, 69–91.CrossRefGoogle ScholarPubMed
Win, T. T., Jalloh, A., Tantular, I. S., Tsuboi, T., Ferreira, M. U., Kimura, M. and Kawamoto, F. (2004). Molecular analysis of Plasmodium ovale variants. Emerging Infectious Diseases 10, 1235–1240.CrossRefGoogle ScholarPubMed
Wright, A. D. and Lynn, D. H. (1995). Phylogeny of the fish parasite Ichthyophthirius and its relatives Ophryoglena and Tetrahymena (Ciliophora, Hymenostomatia) inferred from 18S ribosomal RNA sequences. Molecular Biology and Evolution 12, 285–290.Google ScholarPubMed
Zietara, M. S., Rokicka, M., Stojanovski, S. and Lumme, J. (2010). Introgression of distant mitochondria into the genome of Gyrodactylus salaris: nuclear and mitochondrial markers are necessary to identify parasite strains. Acta Tropica 55, 20–28.Google Scholar