Researchers can track cell development through 'genetic barcodes'
 

A newborn is composed of roughly 26 billion cells when he or she enters the world naked, screaming and rather gooey. Figuring out how those multitudes of cells came to be from a single zygote remains among the greatest challenges in developmental bio...

https://www.engadget.com/2018/08/09/...etic-barcodes/