Plasmodium parasites, the eukaryotic pathogen of malaria, express two ribosome types A and S, characterized by temporal expression patterns and rRNA sequence variation. Specialized functions of the S-type ribosomes have been identified in blood-stage parasites, and I hypothesize this is due to rRNA sequence variation in the expansion segments. To address this, I am generating rRNA probes of a specific expansion segment, ES9S, to identify protein interactions specific to the A- or S-type rRNA.