High Genetic Variability in Full-length cox2 and nad6 Genes of Echinococcus granulosus sensu stricto and Echinococcus ortleppi Recovered from Cattle

Echinococcus granulosus (G1/G3) and E. ortleppi (G5) are prevalent worldwide. Numerous studies have been conducted to characterize these parasites and utilized mainly cox 1, nad 1, and nad 5 genes. However, there is a lack of comprehensive global data on genetic diversity in E . granulosus and E. ortleppi based on cox 2 and nad 6 genes. The current pilot research work was executed to look into the genetic variation of the E . granulosus (G1/G3) and E. ortleppi (G5) populations in Pakistan using cox 2 and nad 6 and infer phylogenetic relationships with other E . granulosus sensu lato populations. Followed by cyst collection from slaughtered cattle in Pakistan and DNA extraction, the full mitochondrial cytochrome oxidase 2 and NADH dehydrogenase subunit 6 were amplified. After confirmation of the identity of isolates through BLAST analysis, population indices pertaining to neutrality and diversity were calculated using the DNASp program. MJNs were constructed using PopArt for intraspecific data investigation. Nucleotide sequences (n=17) analyzed in this investigation were matched with GenBank reference sequences and Echinococcus genotypes G1 (n=5) and G3 (n=7) were discovered. Five sequences were identified as E . ortleppi (G5). For E. granulosus (G1/G3), a high haplotype diversity (Hd=1.00) was found for cox 2 (582 bp), nad 6 (456 bp), and concatenated cox 2- nad 6 (1038 bp) gene sequences. The overall value of Tajima's D for the entire population was negative and insignificant. Regarding E. ortleppi , cox 2- nad 6 pi and Hd were 0.07290 and 1, respectively with insignificant Fu's Fs. A dataset of 40 cox 2 and 35 nad 6 sequences was utilized to form a medianjoining network to compare the geographical kinship between the Pakistani isolates and sequences reported elsewhere. The analysis of concatenated cox 2- nad 6 obtained in this study revealed a high haplotype diversity (1.00) while low nucleotide diversity (0.08207) was observed. Non -significant values of Tajima's D = -0.54361 and Fu's Fs = 1.303 were observed. High haplotype diversity in the current study shows a significant level of genetic divergence across haplotypes. The amalgamation of low pi and high Hd indicates population expansion. We recommend amplifying a greater number of isolates in the future to ascertain the resolution power of cox 2 and nad 6 genes in the context of genotype differentiation.