If you're looking into joining the Li lab as a grad student you may be trying to figure out the Cluster/Committee/Department administrative structure in the Biological Sciences at the University of Chicago.
In addition to your standard departments there are "committees", which are inter-departmental graduate programs, and "clusters", which are groups of related departments and committees that coordinate admissions.
Current students in the Li Lab were admitted through the Department of Ecology & Evolution, in the Darwinian Sciences Cluster, or the Committee on Genetics, in the Molecular Biosciences Cluster, although others routes are possible.
Carolyn Johnson, the program administrator for Darwinian cluster, can help you out if you have more questions about applying.