Phylogenetic relationships of the apicomplexan protist Sarcocystis as determined by small subunit ribosomal RNA comparison.

Reverse transcription of total cellular RNA was used to obtain the partial nucleotide sequence of the small subunit ribosomal RNA (srRNA) of Sarcocystis gigantea. The sequence was compared with the homologous sequences of 24 other eukaryotes. Phylogenetic analysis of the semiconserved regions by 4 different tree-building methods using bacteria as an outgroup all concur in showing monophyly of Sarcocystis gigantea and Toxoplasma gondii to the exclusion of all other taxa for which homologous sequences are available.