planarian flatworms can regenerate an entire individual from small fragments of their body. Regeneration always starts by creating the head,because the regenerating region expresses genes that instruct stem cells to create a head at its tip. lf this mechanism could be applied to induced pluripotent stem (iPS) cells, it might be possible to control cell differntiation and regeneration at the gene level. this could lead to control cell differentiation and regeneration at the gene level this could lead to signitices in organregeneration