Figure 2.

Types of SSU ribosomal RNA expressed in Plasmodium spp. life cycle. A-type rRNA (the red inner circle) is transcribed early in the exoerythrocytic cycle of Plasmodium in liver cells of a vertebrate host, being dominant until the zygote stage in the midgut of a mosquito. S-type rRNA (blue inner circle) expression starts in zygotes and is maximally transcribed in the sporozoite stage at salivary glands of mosquitoes; being reduced after infection of liver cells. The O-type rDNA (green inner semicircle) was only described in P. vivax, which is expressed in maturing ookinetes and oocysts and was not detectable in sporozoites from mosquitoes.