This variations could be linked to environmental factors and mutations.

interest

Hi Nashaat Ghalib

lot of these variations occur on environmental pressure, as for the skin cells where UV induce variations but not all variations survive due to DNA repair functions until cells are stressed and all process tired and she down. another paper on the same topic is : https://science.sciencemag.org/content/364/6444/eaaw0726.long.

fred

Thanks dear Frederic Lepretre that is nice point

Interesting discussion. Following

You are welcome