Scientists grow proto-eyes in the laboratory

In a major advance toward regenerative medicine, researchers have for the first time coaxed stem cells from a mammal into becoming an embryonic eye, according to a study released Wednesday. The results, published in Nature, show that growing a complex human organ inside a petri dish - while still a long way off - is no longer the stuff of science fiction.
They also point the way to new treatments for diseases that rob people of sight, and even the possibility of one day restoring vision with transplanted retinas generated from a patient's own stem cells, say outside experts. In laboratory experiments with mice, researchers led by Yoshiki Sasai of the RIKEN Center for Developmental Biology in Kobe, Japan began with pluripotent stem cells, the universal starter kit for virtually every specialised cell in an organism.
Up to now, stem cells have been seen mainly as a potential source of replacement tissue - such as muscle, liver or heart - composed of a single type of cell. Generating a more complex set of cells, or an entire organ, was thought to be dependent on complicated chemical interactions with neighbouring tissues during gestation, and thus impossible outside the natural process of cell division and growth.