Board Thread:Naruto Discussions/@comment-945885-20140709082448/@comment-24593592-20140719194529

Skitts wrote: That seems to take biology backwards, that is, these mutations are passed on, but her descendants never have more than one of them.

Btw, I would like to point out that it's established Indra inherited the eyes of the Sage while Asura inherited his body. You can't apply real world biology to this.