Open Access Research

Integrated taxonomy: traditional approach and DNA barcoding for the identification of filarioid worms and related parasites (Nematoda)

Emanuele Ferri12, Michela Barbuto2, Odile Bain3, Andrea Galimberti2, Shigehiko Uni4, Ricardo Guerrero5, Hubert Ferté6, Claudio Bandi1, Coralie Martin3 and Maurizio Casiraghi2*

Author Affiliations

1 Dipartimento di Patologia Animale, Igiene e Sanità Pubblica Veterinaria, Sezione di Patologia Animale e Parassitologia, Università degli Studi di Milano, via Celoria 10, 20133 Milano, Italy

2 Dipartimento di Biotecnologie e Bioscienze, ZooPlantLab, Università degli Studi di Milano Bicocca, P.zza della Scienza 2, 20126 Milano, Italy

3 Parasitologie Comparée et Modèles expérimentaux USM 307, Muséum National d'Histoire Naturelle, 75231 Paris Cedex 05, France

4 Department of Medical Zoology, Osaka City University Medical School, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585 Japan

5 Instituto de Zoologia Tropical, Faculdad de Ciencias, Universidad Central de Venezuela, PO Box 47058, 1041° Caracas, Venezuela

6 JE 2533 USC AFSSA «Vecpar» UFR de Pharmacie, 51 rue Cognacq-Jay, 51096 Reims, France

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Frontiers in Zoology 2009, 6:1  doi:10.1186/1742-9994-6-1

Published: 7 January 2009

Abstract

Background

We compared here the suitability and efficacy of traditional morphological approach and DNA barcoding to distinguish filarioid nematodes species (Nematoda, Spirurida). A reliable and rapid taxonomic identification of these parasites is the basis for a correct diagnosis of important and widespread parasitic diseases. The performance of DNA barcoding with different parameters was compared measuring the strength of correlation between morphological and molecular identification approaches. Molecular distance estimation was performed with two different mitochondrial markers (coxI and 12S rDNA) and different combinations of data handling were compared in order to provide a stronger tool for easy identification of filarioid worms.

Results

DNA barcoding and morphology based identification of filarioid nematodes revealed high coherence. Despite both coxI and 12S rDNA allow to reach high-quality performances, only coxI revealed to be manageable. Both alignment algorithm, gaps treatment, and the criteria used to define the threshold value were found to affect the performance of DNA barcoding with 12S rDNA marker. Using coxI and a defined level of nucleotide divergence to delimit species boundaries, DNA barcoding can also be used to infer potential new species.

Conclusion

An integrated approach allows to reach a higher discrimination power. The results clearly show where DNA-based and morphological identifications are consistent, and where they are not. The coherence between DNA-based and morphological identification for almost all the species examined in our work is very strong. We propose DNA barcoding as a reliable, consistent, and democratic tool for species discrimination in routine identification of parasitic nematodes.