The liver genes are masked in a heart cell and vice versa.
A heart cell is different from a liver cell because it uses different genes.
Today, his heart cell models are so accurate that pharmaceutical companies use them to test for the effects of drugs on cardiac arrhythmia.
These controls are what determines a cell's future: whether it grows into a heart cell, a muscle cell, or perhaps a brain cell.
Instead, these scientists are trying to understand what the chemical and genetic switches are that turn something into a heart cell or muscle cell.
They could be used to study and treat diseases and to study the basic biology of what determines a cell's destiny — why a heart cell becomes a heart cell, for example, instead of a brain cell.
Using so-called gene expression chips, scientists will be able to detect which genes are active in a heart cell and which are active in a kidney cell, shedding light on what makes those cells develop differently.
As a medical student in 1960 he developed the first viable mathematical model of a working heart cell, showing how it was possible to reproduce the heart's rhythm by modelling the changing electrical potential within it.
For example, in Noble's heart cell model, if you remove the pacemaker gene protein - first discovered in 1997 - which generates 80% of the heart's electrical current, you might expect that the heart would stop or go haywire.
Rather, the accelerating discoveries relate to what determines a cell's fate — is it going to be a heart cell, a liver cell, a brain cell?
Under resting conditions the heart cell is primarily permeable only to positively charged potassium ions, which slowly leak into the cell.
