Board Thread:Warhammer 40k General Discussion/@comment-91.224.27.226-20131031140001/@comment-8881468-20140103024918

it could not be explained by mutation, considering that all warriors are given the same gene seed of 1 legion.

if you have 1 person, okay mutation but hundreds or thousands of astartes of different age (scars and so on are not that hideable)) with the same mutation that makes them different form the smurfs, or any other legion... (mind you, this will be passed on into future generations through their progenoid glands) (we also do not know how organs from different progenoid glands would react with one another, maybe the one seeing the other as  different tissue and triggering an autoimmune reaction -- which would be problematic when considering implantation of gene seed into candidates), aka: either you refuse their passing on of gene seed or you control to always pass on gene seed form 1 source, as to keep it pure, unmixed and thus you always have a group of people standing out.  and then you got the "mommy why do I look different form the others" problem.

they left out 2 legions for a purpose: so that poeple can make their own chapters, 1 traitor 1 loyal.. fanservice, they will not make anything else but hints.