Figure 4.

Conservation and apparent turnover of regulatory regions in the IGK gene encoding immunoglobulin κ. The intronic enhancer discovered by interspecies conservation of noncoding DNA (Emorine et al. 1983) is toward the right end; it lies in a region likely to be under evolutionary constraint, as shown by the mammalian phastCons and conserved element tracks (Siepel et al. 2005). This site and a second, nonconserved site are both bound by NFKB (RELA subunit) in the lymphoblastoid cell line GM12891, shown as the density of mapped ChIP-seq reads on the last track. The ChIP-seq data are from Kasowski et al. (2010) and the ENCODE project (The ENCODE Project Consortium 2011).