X Zheng

In the bone marrow, as in a barracks, there is a constant roll call. Rookie T cells wait for their first assignment, and for a while they all look alike. But with age, soldiers with a special mark on their uniform start to appear among them: the protein annexin A1. This mark is not a decoration but a brake shoe that keeps the cell from charging into battle.

In a print shop, every page of a book used to be set by hand. One mistake, and the whole print run is at risk. RNA sequencing of the brain looked much the same until recently: each sample demanded hours of manual work, and short reads, like torn scraps of pages, could not be pieced together into the full text of a gene. Now there is a production line that reads every page from start to finish.