Histone variants are not merely static sign posts that influence gene expression. These variants are moved, by other proteins, between different locations in the genome. The new research elucidates the migration patterns of a histone variant during mouse embryonic development. Cells differentiate over time in the growing embryo, and in this process the histone variant migrates to different genomic locations. And the research indicates these movements are orchestrated by three different proteins. As one researcher put it:
Our work shows that the regulation of histone variant localization -- the shape of the so-called epigenetic landscape at different regions of the genome -- is more complex than previously thought.
Or as one writer explained, these findings “hint at an unimagined complexity of the genome.” Nothing in biology makes sense in the light of evolution.