A flagellum is an appendage that operates in a whip-like movement.Two of the essential structures of the flagellum are the radial spoke and central pair. The radial spoke is a protein structure found in the axonemes of eukaryotic flagella that is involved in the mechanical movement. The central pair is a part of the axoneme, which serves as the skeleton of flagella. In this study, flagellate and non-flagellate eukrayotic microbes were analyzed to determine if there were genes that code for the radial spoke or central pair in their genomes. 40 genes related to these structures were inventoried in genomes and transcriptomes of 20 flagellate and non-flagellate eukaryotes. A BLAST based python script was used for gene inventory in each corresponding organism.There was a clear difference in the genomes of the flagellates and non-flagellates where flagellates contained at least 60 percent of the radial spoke and central pair genes found in Chlamydomonas. However, even non-flagellates contained various percentages ranging 9.5-71 percent of these flagella genes. This result suggests that non-flagellate amoeba were ancestrally flagellated; however, they lost the structure while keeping some of the genes necessary for flagellum formation.
