TheVenerableCain WanderingEng CraigEllsworth: I just discovered the Vorkosigan Saga and have bought the first book - Falling Free. That is pretty much exactly as I had envisaged my adapted humans. Oh well, que sera sera!It relates the creation of the "Quaddies", genetically modified people who have four arms, the second pair appearing where unmodified humans would have legs. They were intended to be used as a space labor force, not only superbly adapted to zero-gravity but unable to function "downside" in any but the lightest gravitational field.
Meh, it's never the end of the world to discover something similar it what you thought was an original idea. Indeed, it was original to you when you came up with it, and if you're trying to make an original world, I like to think that counts enough. But of course, if it's a bummer to you, there are always ways of changing specifics to set your world apart. Make your adapted humans look different but act the same; or give them a different culture or function. I've got a race in one of my worlds that I can't help but think look like "Klingon Hagrids", but I try to do what I can in altering their appearance so that my two-word description becomes less and less accurate on both counts. I make their Klingon-like head ridges more exaggerated to the point of becoming vestigial horns or antlers, for instance. Enough play like that and you can avoid the direct comparison, if that's what you desire to do.