Board Thread:Warhammer 40k General Discussion/@comment-6767898-20130227013545/@comment-7186329-20130328171312

It was never stated otherwise, it is impossible to prevent miniscule changes to any gene seed, or anything, in the span of 10 000 years. There are even some extreme cases where a chapter actually grows horns and too much bone, the dragons? i believe, if the primarchs do return to their chapters the total stabilization and purification of the gene seed might be possible, especially in chapters that have any major mutations to the gene seed.