This group of sequences are defined by the N-terminal domain of a paralogous family of Plasmodium yoelii genes preferentially located in the subtelomeric regions of the chromosomes. There are no obvious homologues to these genes in any other organism. The C-terminal portions of the genes that contain this domain are divergent and some contain other yoelii-specific paralogous domains such as PYST-C2 (IPR006491).