Figure 6 The locationof the SNPs1&2 in EHI_080100 and EHI_065250 genes. Mapping of the informative SNPs within the coding sequences. A) EHI_065250 and B) EHI_080100 genes. Nucleotide
position of the amplicon 5’ and 3’ bases are shown and approximate location of the 5’ (green) and 3’ (red) and the positions and number of the targeted SNPs indicated by vertical lines. The bases involved are bracketed in the nucleotide sequence at this region (shown above). The amino acid sequence with changed residues in red is also shown. Discussion E. histolytica SNPs were identified in amebic DNA isolated from a Bangladesh population by amplicon sequencing. Non-Reference SNPs in the EHI_080100 cylicin-2 gene were significantly associated with the virulence phenotype
(amebic this website liver abscess > asymptomatic > diarrhea or dysentery). We initially analyzed the genetic diversity among 12 sequenced E. histolytica genomes that represented different geographical origins and disease manifestations, and selected a set of 21 polymorphic sites in coding regions where SNPs change the encoded amino acid. The distribution of these 21 non-synonymous SNPs in field isolates and cultured strains of E. histolytica were examined in samples collected from an endemic area in Bangladesh by multilocus sequence typing (MLST). Of 16 loci that passed quality control five were invariantor very infrequent in Bangladesh. Our results are inconsistent with a model of clonality in E. histolytica populations. In a clonal population Dichloromethane dehalogenase we would expect to see strong linkage QNZ disequilibrium between markers, since linkage would not be eroded Compound C manufacturer by recombination and sexual reassortment. In fact, we saw only two identical genotypes in our sample, suggesting a considerable amount of recombination and/or reassortment. Our results support previous observations, based on short tandem repeat DNA sequences, of high diversity among genotypes even within limited geographical areas [18, 21, 24]. Due to this complexity, the
number of whole genomes sequenced in the pilot studies, were not sufficient to predict accurately the SNPs associated with disease. However, 2 out of the 16 loci examined,(EHI_065250 and EHI_080100), were significantly associated with disease in isolates collected in Rajshahi and Dhaka, Bangladesh. One caveat to this study was that the amebic liver abscess samples were collected in Rajshahi but the stools samples were collected at a different location (Mirpur, Dhaka); the differences in the grouping of liver abscess and stool E. histolytica could reflect geographical differentiation . Ali et al. have however previously described different genotypes in liver abscess and enteric samples from the same patients . This suggests a possible genetic selection for parasites with invasive capabilities. Based on our data we suggest a divergent rather than sequential model of the potential to cause severe disease .