title: Cytogenetic evidence for diversity of two nuclei within a single diplomonad cell of Giardia.
abstract: Giardia intestinalis is an ancient protist that causes the most commonly reported human diarrheal disease of parasitic origin worldwide. An intriguing feature of the Giardia cell is the presence of two morphologically similar nuclei, generally considered equivalent, in spite of the fact that their karyotypes are unknown. We found that within a single cell, the two nuclei differ both in the number and the size of chromosomes and that representatives of two major genetic groups of G. intestinalis possess different karyotypes. Odd chromosome numbers indicate aneuploidy of Giardia nuclei, and their stable occurrence is suggestive of a long-term asexuality. A semi-open type of Giardia mitosis excludes a chromosome interfusion between the nuclei. Differences in karyotype and DNA content, and cell cycle-dependent asynchrony are indicative of diversity of the two Giardia nuclei.
authors.affiliation: Department of Tropical Medicine, First Faculty of Medicine, Charles University in Prague, Studnickova 7, Prague 2, Czech Republic. ptumo@lf1.cuni.cz
authors.forename: Pavla
authors.initials: P
authors.lastname: Tůmová
authors.forename: Klára
authors.initials: K
authors.lastname: Hofstetrová
authors.forename: Eva
authors.initials: E
authors.lastname: Nohýnková
authors.forename: Ondrej
authors.initials: O
authors.lastname: Hovorka
authors.forename: Jirí
authors.initials: J
authors.lastname: Král
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000235:genetics; D002467:Cell Nucleus / Q000235:genetics*; D020732:Cytogenetic Analysis; D016054:DNA, Protozoan / Q000235:genetics; D005872:Giardia / Q000166:cytology* / Q000235:genetics*; D007621:Karyotyping; D008938:Mitosis; D008941:Spindle Apparatus
chemical_list: D016054:DNA, Protozoan