Long range chromosomal interactions and first passage process in budding yeast

Chromosomal interaction plays a critical role for nuclear processes including DNA repair, replication, and transcription. One important step during the interaction is the encountering of two chromosome segments, which in statistical physics presents a first passage problem. Here, we use a novel method developed in our lab, chemically induced chromosomal interaction (CICI), to study chromosome motion and the first passage dynamics. We show that both random diffusion and cohesin loop extrusion contribute to intrachromosomal interactions. We also applied polymer physics models to understand the chromosome dynamics.