Modern cell-labelling and imaging techniques are yielding ever-more detailed pictures of how our cells and tissues develop. Originally developed to track developing neurons, the brainbow method allows individual stem cells to be identified with a specific colour, which they pass on to all their successive daughter cells, so whole lineages of cells can be followed throughout development. Its most recent application, in zebrafish, is yielding new insights into the origins of blood cells. Pictured are two zebrafish embryos, 48 hours after fertilisation; in the lower embryo, colour-labelling of blood stem cells has been activated. Challenging previous assumptions, researchers have discovered that blood stem cells compete with each other early in development, and are not uniform, each only producing certain types of blood cells. These findings suggest a new approach to studying the origins of blood cancers, focusing on specific lineages rather than considering whole populations of stem cells.
Written by Emmanuelle Briolat
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