Indeed, far from most of the genome being effectively constant, it can be estimated that every position in the genome has been mutated many, many times over in the human population. And each of us carries hundreds of new mutations that arose during generation of the sperm and egg cells that fused to form us.The author says this is why, so far, things have not been going well in the search for genetic causes of diseases. We're all mutants.
You may remember that great progress was expected immediately when the human genome was decoded. Pundits envisioned a medical revolution that hasn't really occurred so far. That's partly because the biology is a lot more complicated than they contemplated.
You peel a layer back,
and what do you get?
New problems to attack.
No end in sight yet!