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DNA Barcoding - Parasites and Vectors Dan Masiga Molecular Biology and Biotechnology Department

DNA Barcoding - Parasites and Vectors Dan Masiga Molecular Biology and Biotechnology Department. Insects. Vector-transmitted pathogens. Viruses Rickettsia Bacteria Protozoa helminths. UNICEF/UNDP/World Bank/WHO - TDR. TDR Disease Focus African trypanosomiasis Chagas disease

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DNA Barcoding - Parasites and Vectors Dan Masiga Molecular Biology and Biotechnology Department

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  1. DNA Barcoding - Parasites and Vectors Dan Masiga Molecular Biology and Biotechnology Department

  2. Insects

  3. Vector-transmitted pathogens • Viruses • Rickettsia • Bacteria • Protozoa • helminths

  4. UNICEF/UNDP/World Bank/WHO - TDR TDR Disease Focus African trypanosomiasis Chagas disease Leishmaniasis TDR Disease Focus African trypanosomiasis Chagas disease Leishmaniasis Dengue Lymphatic filariasis Malaria Onchocerciasis TDR Disease Focus African trypanosomiasis Chagas disease Leishmaniasis Dengue Lymphatic filariasis Malaria Onchocerciasis Schistosomiasis Tuberculosis Leprosy Dengue Lymphatic filariasis Malaria http://www.who.int/tdr/grants/strategic-emphases/files/matrix.pdf

  5. Distribution of human-infective trypanosomes causing sleeping sickness Animal-infective trypanosomes Are found throughout sub-saharan Africa, with the exception of the Southern tip.

  6. Barcoding tsetse flies and trypanosomes Well fed tsetse tsetse fly feeding T. brucei in blood smear

  7. Tsetse flies and trypanosomes There are about 31 species of tsetse flies, the only members of genus Glossina, are recognized. About 10 tsetse-transmitted trypanosome species and sub-species are known; probably >100 other species. Beyond Africa, T. evansi and T. vivax are transmitted mechanically (without parasite development in the vector)

  8. Tsetse: ITS 1 Trypanosomes: Satellite DNA; small-subunit ribosomal RNA (ssu rRNA) gene Barcoding tsetse and trypanosomes Loci that have been used

  9. Identification of trypanosomes based on satellite DNA Satellite DNA is defined as “a portion of DNA in eukaryotes whose density differs from that of the majority of DNA and that consists of short, repeating sequences of nucleotide pairs (typically 5-500 bp long).

  10. Trypanosome phylogeny (and ID) using ssu rDNA (18S rDNA locus)

  11. Current phylogeny is based on 18S rDNA phylogeny is based on 18S rDNA (taken from Hamilton et al., 2004)

  12. Can COI be used for barcoding trypanosomatids?

  13. glycosomes Inside a trypanosome mitochondrion

  14. 20-50 identical maxicircles (20-40 kb) encode 18 protein encoding (12 non-functional) genes, 2 rRNAs and a few guide (g) RNAs. 5000-12000 heterogeneous minicircles encode (over 900 different) small guide RNAs. Maxi- and minicircles are interlocked in a giant catenate. Dyskinetoplastic cells lack minicircles, maxicircles or both, e.g. T. evansi. Cannot be transmitted by Tsetse. Kinetoplast DNA (mitochondrial DNA) EM of the periphery of an isolated kDNA network Network of minicircles Prof. Christine Clayton condensed network

  15. Some benefits of using COI • A single locus of accessible size. • Resolve classification of Glossina at sub-generic level (3 or 4 have been proposed: fusca, palpalis, austeni & morsitans). • A more accurate indication of relationships and distances, perhaps providing explaining some key phenotypes, e.g. transmission efficiencies.

  16. Lutzomyia spp. (New World ) Phlebotomus spp. (Old World) Lutzomyia longipalpis lapinha TDR image Lib ID 00061063 Sandflies, vectors of Leishmaniasis Species of Leishmania L. major L. aethiopica L. infantum L. donovani L. tropica L. mexicana complex L. guyanensis L. naiffi L. braziliensis L. tarentolae E. scheideri

  17. Insects

  18. Barcoding and epidemiology/disease control

  19. Global view of endemic regions for leishmaniasis With such a wide distribution, you can start small, but must network to advance.

  20. NHGRI Awards $13M for Next Generation Sequencing Technologies [October 4, 2006] NEW YORK (GenomeWeb News) – The National Human Genome Research Institute has awarded eleven grants worth a total of more than $13 million to develop technologies that will lower the cost of DNA sequencing. The agency has a near-term goal of lowering the costs of sequencing a mammalian-sized genome to $100,000, and to eventually cut the cost of whole-genome sequencing to $1,000 or less. Lowering the cost will make genome sequencing possible as part of routine medical care, NHGRI said. Nine grants fund researchers developing technologies that will make the $1,000 genome possible and two grants for researchers working on the $100,000 mammalian genome:

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