Structurally distinct, stage-specific ribosomes occur in Plasmodium.

Two structurally distinct nuclear genes code for cytoplasmic small subunit ribosomal RNA's in the parasite Plasmodium berghei. Stable transcripts from one of the ribosomal RNA genes are found almost exclusively in those stages of the life cycle that develop in the mosquito. When the parasite infects the mammalian host, transcripts from the second gene become the predominant small subunit ribosomal RNA species.