chromatin (Gilbert et al. 2004), or partitioning between aqueous and phenol phases (Nagy et al. 2003), have been used to provide insight into packaging of genomic regions. Finally, in addition to separation methods, proximity ligation methods for analysis of chromosomal interactions, such as 3C and related techniques (Dekker et al. 2002), use chemical crosslinking to capture physical interactions between pieces of DNA (presumably mediated by proteins), providing a contact map for the folding of the genome.
