Board Thread:Warhammer 40k General Discussion/@comment-25618639-20141206200938/@comment-8881468-20141224004118

space marines change their skeleton during implanjtation, they might change their teeth, they change their eyes, maybe their skin and we do not want to go into the state of the indicvidual inplants depending on the gene-seed.

(sienote: you actually have only one ultramarine librarian, who is not white in the whole canon, the rest share the complexion of roboute.)

each legion has it's own physicque and traits, whcih are recognisable for members of the other legion.

you will be able to tell a raven guard from a salamander or an ultramarine or an imperial fist., especially if you are one of those in one legion and know what the other legions are about.also:as  we have to theorize on gk knight gene seed overriding other gene seed ( "pandorax" as source) but the primarch gene-seed being equally strong, it is quite hard to say that the differences would not make it easily recognisable.

there is something called common sense, you might wanna use that superpower