Sequence phylogenetic analysis and associative genetic diversity of Sarcocystis hirsuta based on 18S rRNA gene

Background: Sarcocystis hirsuta, a tissue cyst-forming coccidian parasite of cattle, is worldwide in distribution. In spite of its global presence, limited literature is available on its characterization studies. No literature is available from India on molecular aspects of S. hirsuta. The present study was designed to characterize the isolates of S. hirsuta on the 18S gene locus. A total of five isolates of S. hirsuta were characterized. PCR products were cloned, sequenced, and compared with other sequences across the world. A phylogenetic tree was constructed based on the maximum parsimony (MP) method with the tree-bisection-regrafting (TBR) algorithm. Results: An appreciable genetic variability was noticed between various S. hirsuta isolates at the 18S gene locus. Sequences generated from the present study (MN121567-MN121571) represented two haplotypes with 99.74-100.00% nucleotide homology within themselves. Alongside, a nucleotide homology of 97.82-99.92% was observed between Indian isolates and isolates across the globe. The two haplotypes were markedly distinct from each other with 3 nucleotide substitutions within themselves. Overall, Indian isolates of S. hirsuta were close to those from China and Vietnam than to those from New Zealand, Brazil, and Germany. Conclusion: The present communication describes the first report of phylogenetic characterization of S. hirsuta from India. The findings are very much important in delineating the evolutionary phylogenetics of S. hirsuta.