Ambitious 'Human Cell Atlas' Aims To Catalog Every Type Of Cell In The Body

"If you flip open a biology textbook or do a quick search on Google, you'll quickly learn that there are a few hundred types of cells in the human body."

"'And it's true, because in broad categories, a few hundred is a good characterization,' says Aviv Regev, a core member of the Broad Institute, a genetics research center in Cambridge, Mass."

"But look a little closer, as Regev has been doing, and a far more complicated picture emerges."

"'No one really knows how many there will be,' she says. Immunologists had already counted more than 300 in the immune system alone. The eye's retina, other research showed, has more than 100. How many in the whole body? Regev won't even try to predict."