Sexual reproduction and meiotic sex are deeply rooted in the eukaryotic tree of life, but mechanisms determining sex or mating types are extremely varied and are only well characterized in a few model organisms 1 . In malaria parasites, sexual reproduction coincides with transmission to the vector host. Sex determination is non-genetic, with each haploid parasite capable of producing either a male or a female gametocyte in the human host 2 . The hierarchy of events and molecular mechanisms that trigger sex determination and maintenance of sexual identity are yet to be elucidated. Here we show that the male development 1 ( md1 ) gene is both necessary and sufficient for male fate determination in the human malaria parasite Plasmodium falciparum . We show that Md1 has a dual function stemming from two separate domains: in sex determination through its N terminus and in male development from its conserved C-terminal LOTUS/OST-HTH domain. We further identify a bistable switch at the md1 locus, which is coupled with sex determination and ensures that the male-determining gene is not expressed in the female lineage. We describe one of only a few known non-genetic mechanisms of sex determination in a eukaryote and highlight Md1 as a potential target for interventions that block malaria transmission. A non-genetic mechanism of sex determination in the human malaria parasite, Plasmodium falciparum , is described, and the male development 1 gene is identified as a potential target for interventions that block malaria transmission.
【저자키워드】 Transcription, Gene regulation, Evolutionary developmental biology, Parasite genetics,