One thing that bothered me about the Battlestar Galactica finale was that Colonial humans, who had apparently evolved on a world entirely separate from our Earth, could interbreed with the African tribes they encountered in “Daybreak”.
But… this can work. And I think I can even explain the head characters too.
You see, Battlestar Galactica takes place approximately 150,000 years ago. Homo Sapiens arose closer to 200,000 years ago. This is a lot of time for some interesting stuff to happen.
I propose that the Lords of Kobol were an alien species that kidnapped some of the earliest Homo Sapiens from Earth and settled them on Kobol, perhaps as a zoo, perhaps for slave labor. At least some parts of Kobol had a climate and ecology similar to some parts of Earth, if we assume this similarity was global, then it’s easy to imagine similar racial differences arising. Perhaps the Lords of Kobol played around with this- introducing some degree of artificial selection can vastly speed evolution.
At some point, one of the Lords of Kobol decided that what they were doing to the humans was immoral. This lead to the overthrow of the other Lords, the creation of the 13th Tribe(perhaps as warriors against the Lords) and the Exodus. Enough confusion occurred in these days that the oppressor Lords were remembered as good, and the renegade as evil.
The renegade then, over the years, used some of his species advanced technology to help guide Human and Cylon alike on to a better path. He’s the one that Head Baltar says doesn’t like to be called God. He’s the One True God the Cylons and some humans worshipped. He gave Kara Thrace a new body and viper to return to the Fleet. Pythia was likely his servant, though whether or not she knew who she was really working for is uncertain. Maybe he even encouraged the retention of the old religion, so that he could work in shadow undisturbed? The head characters, as of Daybreak, do appear to be entities in their own right, but I think they are clearly his servants. Perhaps members of his own species, perhaps AIs, perhaps something else entirely.
So, the reason Colonial humans could interbreed with the African humans they encountered in Daybreak- they were all humans. The story of the Colonial humans, like that of all humans, began in Africa. Their journey came full circle- they weren’t fleeing towards a new home, they were *returning* home from a temporary refuge in the Colonies.