TITLE: Folding DNA: A hierarchy of time, energy and length

SPEAKER: Dr. Thomas Bishop,

TIME: *** Tuesday Jan. 29, 2002 at 4 PM ***

PLACE: George P. Williams, Jr. Lecture Hall, (Olin 101)

*** Note unusual day of the week ***

A length of DNA of approximately one meter is contained within the nucleus of every human cell. Since the nucleus itself has a diameter on the order of 1 µ, the need for some sort of compaction or folding of the DNA is obvious. It is known that histones fold DNA into nucleosomes and condensed chromatin. How these folds are organized and how the folding itself may play a role in the biologic functionality of the DNA are just beginning to be understood. Using a continuum model of DNA that is based on the theory of elastic rods, Dr. Bishop will demonstrate how structure and dynamics are interrelated. Thus, the folding itself affects the propagation of a mechanical disturbance through DNA. Assuming a simple geometry for the folding of DNA, effective elastic properties for the folded structures can also be deduced by comparison with models of springs. Taken together, these results demonstrate how folding creates a hierarchy of time, energy and length.