Whole genome SNPs analyses unravel Echinococcus species phylogeny

LUCAS MALDONADO; NATALIA MACCHIAROLI; MARA ROSENZVIT; LAURA KAMENETZKY

Ciudad de Buenos Aires

Conferencia; ISCB-LA A2B2C Bioinformatics Conference; 2016

ISCB-LA A2B2C

Background: The parasite Echinococcus canadensis (G7) (phylum Platyhelminthes, class Cestoda) is one of the causative agents of echinococcosis, a worldwide chronic zoonosis affecting humans and animals, together with Echinococcus granulosus (G1) and Echinococcus multilocularis. currently, there is no unequivocal taxonomic classification of Echinococcus species, neither genomic analysis that could reveal particularities among these genus.Results: In the present study we performed whole genome SNPs analyses by mapping reads from genomic DNA of Echinococcus species. Homozygous and heterozygous variant sites were identified and the effect on coding regions was predicted. In general terms, we observed more SNPs between E. canadensis (G7) and E. granulosus (G1) (778,742) than between E. canadensis and E. multilocularis (328,604), not only in the whole genome but also in coding regions. Furthermore; we used the SNPs to perform phylogenetic analyses. Homozygous SNPs were selected and concatenated and resulting alignment was used to create phylogenetic trees. This analysis showed a higher genetic distance between E. canadensis (G7) and E. granulosus (G1), than with E. multilocularis. For further SNP validation; we performed PCR amplification followed by direct sequencing of coding regions of some genes. All SNPs selected, 1 Indel and 48 SNPs (24 synonymous and 24 Non-synonymous) were confirmed by PCR and sequencing.Conclusions: Conversely to early studies on Echinococcus phylogeny based on few nuclear genes or complete mitochondrial genome data, whole genome SNPs studies allowed us to perform phylogenetic analyses that revealed a more distant phylogenetic relationship between E. granulosus (G1) and E. canadensis (G7) than expected.