[freespirited]

This raises the question: if two people can have identical DNA sequences and yet be so different

I wouldn't describe identical twins as "so different."

It's lost on me why the author thinks it is news that a variety of factors affect gene expression.

[GodGunsGuts]

It’s not just some generic factor. The epigenetic code actually controls the genetic code. And, as it turns out, they are finding additional codes that make the genetic code perhaps the simplest code of them all.