Stem Cells contain 100% of DNA/RNA for every cell type and are defined by their ability to differentiate into other, more specialized cell types. When one stem cell divides into two (which are then called daughter cells), three things can happen to the new cells: Both cells can continue being stem cells, both cells can differentiate into a new cell type, or the cells can go their separate ways, with one maintaining the properties of a stem cell and the other becoming specialized.
Our research program (in partnership with 4 Tier 1 universities) has shown that while stem cells have been studied for decades, we still do not understand how they make this commitment when they divide. When all daughter cells are the same cell type, this is called symmetric division. That’s true whether they continue being stem cells or become specialized. When one cell stays a stem cell and the other differentiates, it’s called asymmetric division. This happens about 30 percent of the time.
The beauty of asymmetric division is that you’re maintaining the sustainable balance in your stem cell numbers. If every time a stem cell divides, it loses its identity as a stem cell, eventually all the stem cells are depleted. And if all the cells remain stem cells, you’ll never get the variety of specialized cell types needed to rejuvenate and regenerate the individual's tissues.