The 42nd In Silico Megabank Research Seminar will be held on Friday, December 13.

This Time, we will be welcoming Dr. Masafumi Nozawa, National Institute of Genetics as our lecturer, and he will be speaking on “A novel approach based on interspecies comparison to trace the evolution of dosage compensation.”

・Date/Time: December 13(Fri.) 17:00‐18:30
・Venue: Conference Room 1(2nd Floor), Tohoku Medical Megabank Organization
・Title: A novel approach based on interspecies comparison to trace the evolution of dosage compensation
・Lecturer: Masafumi Nozawa（Center for Information Biology, National Institute of Genetics）

＊This lecture is transferable as a class in the medical research-related lecture course.

・Abstract: Evolution of sex chromosomes is normally initiated by assembling of sex-determining genes and sexually antagonistic genes into a pair of autosomes. Recombination between proto-X and proto-Y chromosomes derived from this pair is then suppressed, because these genes must be tightly linked to maintain sexes. This promotes the divergence of these chromosomes and makes the authentic X and Y chromosomes. At the same time, the Y chromosome is gradually degenerated due to the accumulation of mutations and transposable elements. When Y-linked genes are inactivated or deleted due to the inefficacy of natural selection, their orthologous X-linked genes become monoallelic (or hemizygous) in males, which results in dosage imbalance between sexes as well as between chromosomes in males. Since this imbalance could potentially be deleterious in the evolution of heteromorphic sex chromosomes, it has been thought that there must be some mechanisms to compensate the imbalance. In this context, the concept of dosage compensation was proposed. Indeed, this concept has widely been accepted in many organisms, such as humans and nematodes. Yet, most of these conclusions are based on the results that gene expression levels are similar between sexes and/or between chromosomes and it remains to be elusive how dosage compensation has evolved. To trace the evolutionary process of dosage compensation, I have compared the gene expression on the so-called neo-X chromosome in Drosophila pseudoobscura with that on the orthologous autosomes in other species. In this presentation, I would like to discuss about the results obtained so far and introduce my future plans.

・Organizer : Yukuto Sato, Masao Nagasaki

Access : http://www.megabank.tohoku.ac.jp/english/info/access.html