What is the ancestral origin of the gene causing the Ecuadoran tribe, the Waorani, to sometimes have six fingers and six toes, and occasionally, two rows of teeth?

As you saw intuitively, this is because of prior interbreeding by the Anunnaki among this group of people and the genes for these anatomical characteristics have simply persisted through dominance and can still be exhibited today. This is an ancient interaction, so other characteristics have faded but the presence of these anatomical differences, which are quite striking and characteristic of the Anunnaki, can still be on display. There are many other genes that are favorable in terms of health and well‑being because of the optimization done by the Anunnaki themselves being master geneticists.