Do the other root races include Arcturian and Anunnaki as well? What about the Sirians, are they an offshoot of the Reptilians also?

The Sirians are not of Reptilian origin and are one of the four root races. The root races in question are not all races you know of, so the Reptilian influence is significant as a percentage because it is a major aspect of the Pleiadian makeup, the latter being one of the four root races. This was deliberately selected as a criterion because one of the most pressing needs for the divine human as an asset in the contest between the light and the darkness is to solve the problem of the Reptilian corruption of things, the darkening that has happened over the eons, and of the Anunnaki as well. This is why the genetic makeup incorporating characteristics from all of the extraterrestrial races, including the Arcturians, the Anunnaki, and the Reptilians, are significant components. Keep in mind this is not to your detriment. The characteristics we speak of through the genetics are positive attributes. The corruption, the evil, is solely the consequence of the spirit meddler interference on a long-standing basis to corrupt them from within as functioning beings, and this has greatly damaged their culture and in turn corrupted them genetically, so there has been a degradation across the board for all three alien races at the hands of the spirit meddler cohort. Your genetic endowment was of those aspects of a pristine nature that conferred capability and basic functioning for those extraterrestrial lineages that make them special and with high capabilities, talents, and skills, so this is an asset, not a liability. It also aligns you with their karma in terms of a resonance because there will be an intertwining of karma as a consequence of the genetic interplay being signaled primarily through the extradimensional DNA components shared among the extraterrestrial and human lineages.