sentences:  If, however, the adult stem cells are using an immortal DNA strand mechanism, they are obligated to retain the unlabeled 'immortal' DNA, and will release all the newly synthesized labeled DNA to their differentiating daughter cells in two divisions.Some scientists have combined the two approaches, by first using one DNA label to label the immortal strands, allowing to adult stem cells to begin dividing asymmetrically, and then using a different DNA label to label the newly synthesized DNA.Thus, the adult stem cells will retain one DNA label and release the other within two divisions.