The Gandarium are apparently another form of alien, only semi-sentient.
They are the bridge between the human DNA and the alien DNA, which allows them to be unified into a single DNA strang.
The granilith is shrouded in mystery.
It seems to be some sort of religious icon, but it's more than iconic; it's functional and very powerful. Its intended use was transport between Earth and Antar. However it has been utilized in a variety of ways.