Cloning and sequencing of beta-tubulin and internal transcribed spacer-2 (ITS-2) of Eimeria tenella isolate from India.

Beta-tubulin is an important multifunctional protein of eukaryotes abundant in the cytoskeleton and responsible for the formation of tubulin, structures responsible for cell morphology and which aid in motility and intracellular transportation. It has been used as a genotypic marker for studying the evolutionary history and phylogenetic relationships between eukaryotic organisms. Internal transcribed spacers of the ribosomal RNA genes have been widely used for typing inter-species and intra-species variation. An Indian isolate of Eimeria tenella was genotyped following the cloning and sequencing of beta-tubulin and internal transcribed spacer-2 (ITS-2) and compared with other reference isolates of E. tenella. The β-tubulin has 99 % intra-species similarity at the gene level and the functional homology of the protein is very high with more than 95 % amino-acid similarity across the Apicomplexa. The ITS-2 sequence had a similar pattern of nucleotide base arrangement with 99 % homology to Houghton and Nippon strains of E. tenella.