84-90Spirulina/Arthrospira is a species of cyanobacteria used in health foods, animal feed, food additives and fine chemicals. The present study conducted a comparison of the 16S rRNA and cpcBA-intergenic spacer (cpcBA-IGS) gene sequences in Spirulina/Arthrospira strains from culture collection of CCUBGA, IARI, New Delhi. All the strains of Spirulina used in this study had shown nearly 99% similarity amongst them. About fifty sequences (cpcBA-IGS) of Spirulin a strains taken from NCBI with ten from the present strains of Spirulina, a neighbour-joing (NJ) tree was constructed with the help of MEGA 5.0. The tree showed 99% similarity. All the sequences were put to Multiple Sequence Alignment with the help of T-Coffee (version 7.38) and BioEdit (version 7.38) software. Similarity studies undertaken based upon 16S rRNA and cpcBA-IGS genes sequence analysis indicated similarity coefficient of 0.84. S. platensis and Arthrospira sp. showed 100 percent similarity. Therefore, the current study supports some previous conclusions based on 16S rRNA gene and cpcBA-IGS sequences, which found that Arthrospira taxa are monophyletic. However, compared to 16S rRNA sequences, cpcBA-IGS sequences might be better suited to resolve close relationships and interspecies variability
