Biologists have grown human retina tissue from scratch to learn how the cells that let us see in color are made.
The work may lay the groundwork for therapies for eye diseases such as color blindness and macular degeneration. It also establishes lab-created « organoids »—artificially grown organ tissue—as a model to study human development on a cellular level.
« Everything we examine [in a retina organoid] looks like a normal developing eye, just growing in a dish, » says Robert Johnston, a developmental biologist at Johns Hopkins University. « You have a model system that you can manipulate without studying humans directly. »
The fate of stem cells
Johnston’s lab explores how a cell’s fate is determined—what happens in the womb to turn a developing stem cell into a cell with a specific function. In the retina research, he and his team focused on the development of cells that allow people to see blue, red, and green—the three cone photoreceptors in the human eye.
While most vision research is done on mice and fish, neither of those species has the dynamic daytime and color vision of humans. So Johnston’s team created the human eye tissue they needed from stem cells…