The polymorphisms of the human enhancer HS1.2. (A) The schematic representation of the human alleles shows the different invariant and variable elements. Up to now 6 different alleles are reported in GenBank, each one identified for the number of copies (*1, *2, *3, *4) of the 40 bp element (40 mer, in yellow). More variability was added by the presence of either a short stretch of cytosines (18 bp, in green) or a different larger element (29 bp, in red) between the enhancer core (in fuchsia) and the first 40 mer. The 3' end of the enhancer (in light blue) also is highly conserved. The green stretches of cytosines parting the 40 mer ranged between 12 and 18 bp. (B) The sequence alignment of four alleles of HS1.2 enhancer sequences colored according to the schematic elements reported in the upper part. The binding for the Oct1, Sp1 and NF-κB factors are reported on the sequence as determined by EMSA experiments.
D'Addabbo et al. BMC Evolutionary Biology 2011 11:71 doi:10.1186/1471-2148-11-71