Board Thread:False Info and Speculative Discussion/@comment-4772791-20160123002637/@comment-26879545-20160219221625

Those differences are minor mutations that develop after they split off from each other. Everything else, of importance, is the same between both twins. Chimerism means they'd have two distinct sets of DNA, which would only be possible if they absorbed a fraternal triplet during gestation, or one of them recieved a transplant from a different person.