Comment by acchow

> There is drift within an organism. The genome on your scalp is different than the genome on your toes

> Also chimeras exist

This provides a deep insight into the nature of multicellular life. People think that a "unicellular organism" eventually turned into a "multicellular organism". But they're not so distinct. The latter is really still just a bunch of cells coordinating, but their coordination is so deep, and the number of cells and functions so large, that emergent properties arise.