Sequence of the Small Subunit Ribosomal RNA Gene from the Hypotrichous Ciliate Euplotes aediculatus1

We have determined the complete nucleotide sequence of the coding region of the small subunit rRNA gene of the hypotrichous ciliate Euplotes aediculatus. It is 1882 nucleotides long and contains several inserts not present in the small subunit rRNA genes of the hypotrichs Oxytricha nova and Stylonychia pustulata. A comparison of the sequences suggests that E. aediculatus is much less closely related to these other two hypotrichs than they are to each other. Although the gene sequence of E. aediculatus is drifting more rapidly than those of these other two species, its faster evolutionary clock is not enough to account for the degree of difference between them.