Molecular phylogenetic relatedness of Frenkelia spp.(Protozoa:
Apicomplexa): to
Sarcocystis falacatula Stiles 1893: Is the genus Sarcocystis
paraphyletic?
Jan Votýpka, Václav Hypąa, Milan Jirků, Jaroslav Flegr, Jiří Vávra, Julius Lukeą
Abstract. The coccidians Frenkelia
microti and Frenkelia glareoli
(Apicomplexa: Sarcocystidae) form tissue cysts in the brain
of
small rodents (intermediate hosts) while oocysts are formed
in
the intestine of final hosts, buzzards of the genus
Buteo. The
inclusion of SSU rRNA sequences of both Frenkelia
species into
the SSU rRNA trees of other, tissue
cysts forming coccidia
strongly supports the paraphyly of
the genus Sarcocystis.
Frenkelia spp. exhibit a close
relatedness to Sarcocystis
falacatula Stiles 1893, a bird-opossum parasite
but also the
causative agent of equine protozoan myeloencephalitis
on the
American continent. As the definition of the genus Frenkelia
is based
on a plesiomorphic character (affinity to the neural tissue) of supposedly
low phylogenetic value, the synonymization of the genus Frenkelia with
Sarcocystis is proposed. This renders the genus Sarcocystis monophyletic.