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Poster
93 |
Selective whole genome amplification (SWGA) for Toxoplasma gondii: How will it help? |
Toxoplasma gondii is protozoan parasite which infects approximately one third of the world’s population. Therefore, a cost effect method to perform whole genome sequencing on Toxoplasma is highly desirable. Whole genome sequencing (WGS) of toxoplasma has been successful using Toxoplasma cultured in laboratory animals. For human clinical samples, however, the technology is limited because of the relative levels of host genomic DNA are much higher than those of the pathogen. Selective whole genome amplification (SWGA) is recent approach which require both bioinformatics steps; and laboratory steps and has been successfully employed to specifically amplify the Malaria parasite, Plasmodium spp., directly from clinical blood samples. The technique involves searching both the parasite genome and the human genome for motifs that are much more common in the parasite genome than in the human genome. These motifs can be then used as oligonucleotide primer targets for the whole genome amplification reaction, thus enriching the target organism DNA concentration.
This method was applied to T.gondii samples, where parasite density was low and where there was no routine ex vivo culture, although species-specific primer sets ware designed for the selective amplification of T.gondii against their background. If SWGA can now be successfully applied to Toxoplasma clinical samples, it would open-up a valuable collection of DNA extracts and these resources would enable significantly more in-depth investigations, improving understanding of the epidemiology, virulence and other traits of this important human pathogen. The successful development of this method will make an important contribution to the ‘3Rs’ (Replacement, Refinement and Reduction in the use of animals in research) by precluding the need for in vivo isolation of toxoplasma from clinical specimens prior to WGS.
