A more comprehensive structural view of chromosome folding is provided by the 3C (Chromosome Conformation Capture) family of techniques, including 3C (Dekker et al. 2002), 4C (Simonis et al. 2006), 5C (Dostie et al. 2006), Hi-C (Lieberman-Aiden et al. 2009), and others. In these methods, chromatin is subject to crosslinking in vivo to capture interactions between chromosomal loci. The genome is then fragmented, typically with restriction enzymes, and DNA ligation is used to capture interactions between chromosomal loci that were in contact with one another in vivo. The abundance of ligation products between two chromosome regions is often interpreted as a measure of frequency/probability of contact, or proximity, between the pair of loci, providing a view of chromosome structure that is somewhat analogous to the view of protein structure generated by NMR techniques.
