Tripleposting for the win.
Humans have an interesting role it seems, among the races. Human DNA has a "universal" quality to it which makes race mixing possible, other races cannot do this. This is what I'm being told now.
For example if you were to try and mate a reptilian with a lyran feline, this can't work. But if you breed a reptilian with a human and a lyran with a human, then you get a half reptilian and a half lyran. Have them mate and you get a human with traits of both lyran and reptilian, for example. Or have the half reptilian mate with a lyran and the lyran now has reptilian traits.
This makes humans valuable and works as a kind of protection from turning extinct. Some people are not going to like hearing this, but it's one of the reasons humans at all have survived.