There also was a study that says that samurai origins go back to an Ainu guard force of a very early emperor. That historical study disappeared off the Japanese Archeological/Anthropological radar screen very rapidly!
I believe if memory serves it was an American author.
I see to recall that too. It started out with certain Samurai families having distinct facial features not shared with the general population. The Japanese also don’t like to remember that Samurai started out as tax collectors and “enforcers” for the daimyos and only later adopted bushido as a code of conduct.
CC