The barcoding of parasitic protists: an example in trypanosomatidae

Desquesnes Marc, Herder Stéphane, Jittapalapong Sathaporn. 2014. The barcoding of parasitic protists: an example in trypanosomatidae. . Mahidol University. Bangkok : Mahidol University, Résumé, 1 p. Joint International Tropical Medicine Meeting (JITMM 2014), Bangkok, Thaïlande, 2 Décembre 2014/4 Décembre 2014.

Résumé : In 2003, Paul Hebert proposed “DNA barcoding” as a way to identify species, using a short genetic sequence from a standard part of the genome the way a supermarket scanner distinguishes products using the black stripes of the Universal Product Code (UPC). A number of targets were selected, such as the mitochondrial gene of cytochrome oxydase (COI), 18S, ITS or 28S of ribosomal DNA, or the spliced leader gene. A 2 steps universal method for protists is under development, using 18S as a first step and another gene for group specific barcodes. In 1996, Mac Laughlin et al have opened the way to identify Kintetoplastids through typing of the Internal Transcribed Spacers of ribosomal DNA, suggesting that ITS sequence are genus or even species-specific. Indeed, ITS1 size and sequence proved to be highly conserved inside a species and variable amongst species, both in Trypanosoma and Leishmania spp. In 2001, ITS1 sequence and size was proved to be distinct in all livestock pathogenic trypanosomes from Africa. In 2002 and later, pan-trypanosome primers (TRYP1) proved to be not only able to detect and distinguish African trypanosomes but also T. lewisi (a commensal parasite of rats, which is occasionally zoonotic) and even Leishmania species, including L. siamensis, responsible of autochtonous leishmaniasis in Thailand (unpublished). A nearly perfect fitting of “species” (a concept hard to defined in some trypanosomatids) and “ITS1 sequence” (and most often size) has been observed, which makes of ITS1 a providential target for barcoding of Trypanosomatidae.

Auteurs et affiliations

• Desquesnes Marc, CIRAD-BIOS-UMR INTERTRYP (THA) ORCID: 0000-0002-7665-2422
• Herder Stéphane, IRD (FRA)
• Jittapalapong Sathaporn, IRD (FRA)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/591940/)

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