12:16 AM
kotesh
They have discovered a striking new feature of the chromatin, the specialized protein molecules that protect and control the giant molecules of DNA that lie at the center of every chromosome. The feature explains how embryonic cells are kept in a poised state so that all of the genome's many developmental programs are blocked, yet each is ready to be executed if the cell is assigned to that developmental path. The developmental programs, directing a cell to become a neuron, say, or a liver cell, are initiated by master regulator genes. These genes have the power to reshape a cell's entire form and function because they control many lower genes.
