TR: Where will this field go in the future?

DM: I think it will change the way degenerative diseases are studied--we'll reduce the whole process of disease to a petri dish. Within a few years, researchers the world over should have access to disease-specific cells that can be turned into cell types defective in a particular disease.

We can also start to study environmental factors. We know sun is important for skin cancer, and smoking is important for lung cancer. But what do we know about Parkinson's, Alzheimer's, ALS, and diabetes? That's hard to study in people because there is a long time between the proximal cause and effect.

Now, scientists can start to think more about how to look at environmental factors in a dish. Let's take food, oxidative insults, pesticides, and extracts and ask how they affect the cells. Scientists can also screen for drugs that slow or stop degeneration of those cells. If that were successful--and now we're talking about a decade-long project--you could make a drug that would slow or stop disease progression.

TR: The Harvard Stem Cell Institute is planning to distribute these cell lines to scientists. Why?

DM: Science clearly works best when you have a lot of bright, motivated people working on these problems. The institute has sent thousands of human embryonic stem-cell lines to hundreds of labs all over the world. We like to think that has been helpful in encouraging basic research on embryonic stem cells. The new cells reported by George Daley and his colleagues may be in some instances even more helpful. They are more than just iPS cells; they are disease-specific stem cells.

TR: Do Harvard scientists plan to make more cell lines?

DM: Yes. These first lines are just the beginning.

TR: Why do you plan to make multiple lines for a single disease?

DM: To continue with the Parkinson's example, suppose you have 50 people with Parkinson's disease. We know that when they have the disease, dopamine neurons are gone. But we don't know how many different ways their neurons are destroyed. Are there 50 different ways those neurons go kaput? It's possible that in every case genetics and the environment conspire to make the same defect in the life of those neurons. If we're going to watch the cells become defective, we want to make 50 dishes from 50 different patients. I hope they all get defective in the same way; that would make it much easier. If not, each variation might require its own strategy for treatment.

TR: How much will the cells cost?

DM: There will be a nominal cost for academics. We don't have a plan for industry yet.