Biology Department Seminar

In this seminar, I will introduce two novel technologies, heavy-ion beam mutagenesis and in silico RLGS which are employed in our study of mutations on bacterial genomes. Energetic heavy ions are one of the densely ionizing radiations with high linear energy transfer (high-LET) and known to have greater biological effect than sparsely ionizing (low-LET) X-rays or gamma-rays. Although heavy-ion beams are widely used as a physical mutagen for plants, their effects on bacterial genomes are not well known. We have characterized the bacterial mutations induced by heavy-ion beams on molecular basis and found that the heavier ions, such as iron, induce larger deletions than lighter ones like carbon. Restriction landmark genome scanning (RLGS) is a two-dimensional DNA electrophoresis method in which restriction enzyme recognition sites are labeled with radioisotopes as “landmarks” and are visualized as spots on an X-ray film. It enables genome-wide scanning of insertions, deletions, and methylation status with high resolution. We have developed in silico simulation software for RLGS based on the whole-genome sequences, and efficiently identified genetic and epigenetic modifications of genome. I will also present a brief overview of biological research at Nishina Center.