Chemical tags on histones help guide early progenitor cells (yellow) toward forming liver cells (blue).

In this embryo, chemical tags on histones—the spools around which DNA is wound—help guide early progenitor cells (yellow) toward forming liver cells (blue). Working with mice, researchers found that distinct patterns of chemical tags on the histones marked progenitor cells for the liver versus the pancreas. The markings could be used to predict cell fates, resolving a longstanding question in stem cell biology about what determines a cell's destiny and possibly offering an important advance in regenerative medicine for conditions like liver failure and type 1 diabetes.

Featured in the June 15, 2011, issue of Biomedical Beat.