About Student Research

Justin Peters (2008-2012)

Getting back to basics with DNA

Each human cell is crammed with 2 meters of DNA, meaning that there is enough of the thread-like DNA in a single human body to reach to the moon and back more than 100 times. The genetic recipes for the microscopic machines of life are all encoded in DNA, and genetic engineering has made DNA familiar to many researchers and students. Surprisingly, although the double-helical structure of DNA has been known for 55 years, the origins of the distinct physical properties of the DNA molecule remain unknown. Justin Peters, a recent graduate of Wartburg College in Waverly, Iowa, is getting back to basics with the DNA molecule by probing its essential features.

Justin's Ph.D. thesis project in the Maher lab at Mayo sought to understand just what it is that makes the DNA molecule stiff. Although long DNA molecules are flexible, short segments of DNA are actually among the stiffest of all natural molecules. Why? Justin experimentally tested a theoretical hypothesis that DNA is very stiff because it is very highly charged. According to this model, the negatively charged rungs of the DNA ladder are mutually repulsive, stretching the molecule into a stiff polymer. Justin asked if DNA is more or less flexible when its electrical charge is adjusted. Justin used a variety of techniques in molecular biology and biophysics to conduct his tests. The results were surprising and shed light on a longstanding mystery about life's longest molecule.