Tracing a family tree often explains a lot about why we are the way we are. The same is true for our cells – they developed from different ancestors and the patterns of genes they switch on, or express, hold secrets to how they behave in our tissues. In this sort of cellular family tree, dots represent cells from a zebrafish, placed in coloured groups by software that spots similar gene expression patterns (discovered using RNA sequencing). Black lines join cells with their ancestors from different stages of the fish’s development. To reveal these patterns, researchers cut up a stretch of DNA inside zebrafish embryos, forcing it to quickly 'heal' in order for cells to divide properly. Unique 'genetic scars' left behind act like barcodes, linking cells in developed fish to their embryonic ancestors. The next job is to follow the development of human stem cells into artificial organs or organoids.
Written by John Ankers
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