Marko's lab applies statistical mechanics and single-molecule micromanipulation -- principally magnetic tweezers -- to chromosome structure and DNA-protein interactions, studying how condensin, topoisomerases, and other nucleoid-associated proteins organize and mechanically stabilize chromatin and mitotic chromosomes in vivo and in vitro. The group combines force spectroscopy with fluorescence microscopy to resolve single-DNA and single-chromosome mechanics at the piconewton scale.