As high-throughput techniques accelerate mapping of epigenetic marks, researchers are racing to find the biological meaning of these marks.
Thanks to the Human Genome Project, researchers worldwide can search a database to see what a gene ‘says’. In just a few years, researchers may also be able to look up when a gene is ‘read’. Or, rather, they will be able to pull up the epigenome, the set of chemical modifications to DNA and DNA-spooling proteins that coordinate how cells use genes.
Even with international enthusiasm, coordination and funding, epigenome mapping will be a long, complicated slog. Although an individual’s genome sequence varies little from cell to cell, each of the 200 or so human cell types has its own epi-genome. Epigenomes also change during development and in response to the environment. Cancer, aging and even behavioral disorders are all associated with epigenetic lesions. “The epigenome space is so much larger than the genome space,” says John Stamatoyannopoulos of the University of Washington in Seattle, who heads one of four epigenome mapping centers funded by the US National Institutes of Health. “The measurement space is absolutely gigantic. No single technology is going to penetrate this with anything approaching completeness,” he says.
Baker M. (2010) Epigenome: mapping in motion. Nat Meth 7, 181 – 86. [article]