Rapid nucleotide sequence analysis of the small subunit ribosomal RNA of Toxoplasma gondii: evolutionary implications for the Apicomplexa.

A method for obtaining a large proportion of the nucleotide sequence of the small subunit ribosomal RNA (srRNA) was applied to the obligate intracellular protozoon Toxoplasma gondii. The method uses reverse transcription of as little as 8 micrograms of total cellular RNA. This fast, efficient method has numerous advantages over traditional gene cloning methods when nucleotide sequences are required for evolutionary studies. A phylogenetic analysis of the srRNA sequence data showed that T. gondii is not especially closely related to any other organism for which srRNA sequences are available, including another member of the Apicomplexa.