Research seminars Tackling the longstanding problem of the position of the root of the eukaryotic tree of life: insights from chromosome segregation machines

Accurate transmission of genetic material is essential for the survival of all organisms. In eukaryotes, the macromolecular protein complexes called the kinetochores drive chromosome segregation during mitosis and meiosis. Given their essential nature in genetic inheritance, it was widely thought that the structural core of kinetochores would be common to all eukaryotes. However, no canonical kinetochore components have been identified in a group of organisms called kinetoplastids, which are evolutionarily highly divergent from yeast or human. To reveal how kinetoplastids achieve chromosome segregation, we identified 25 kinetochore proteins in Trypanosoma brucei (a kinetoplastid parasite that causes African sleeping sickness) and discovered that they constitute kinetochores that are found only in kinetoplastids. We are currently trying to understand how these unconventional kinetochore proteins carry out conserved kinetochore functions to reveal fundamental principles and requirements of eukaryotic chromosome segregation machinery. In this talk, by speculating on a question "Why do kinetoplastids have unique kinetochores, while all the rest of so-far sequenced eukaryotes have conventional ones?", I will discuss two big questions in biology: 1) Where is the position of the root of the eukaryotic tree of life? 2) What is the evolutionary origin of mitosis/meiosis?.

If you want to speak Dr. Akiyoshi in person, please let me know. I will arrange the Interview with him.