(González-Romero et al. 2008; Eirín-López et al. 2009a)
H2A.Z was derived from H2A through a series of mutations that resulted in it being 60% different from the core H2A. This was determined using a system called GWLA methodology which synthesizes two protein structure determining methods. It breaks the protein into fragments and then sequences it. The H2A.Z is highly conserved throughout eukaryotes meaning that the sequence is the same. Because there are few or no mutations this means that the function is very important and a mutation would be lethal. AT