But how clusters of cells get into the bloodstream in the first place has been a mystery, in part because scientists couldn't easily see inside tumors to find out. (sciencenews.org)
Early embryo cells were genetically labeled, and the green and red colors indicate that the two clusters of cells originated from the same cells early in development. (gladstone.org)
But in a surprising find, it appears that in flies all these acts of gallantry are controlled by a single gene active in small clusters of cells in the fly brain. (sciencemag.org)