Long-term regional continuity in certain morphological traits is explained by Alan Thorne's "Centre and Edge" population genetics model which resolves Weidenreich's paradox of "how did populations retain geographical distinctions and yet evolve together?".
Dugoročni regionalni kontinuitet u nekim morfološkim osobinama Alan Thorne je objasnio u svom modelu populacijske genetike "centar i rub", koji rješava Weidenreichov paradoks toga "kako su populacije zadržale geografske razlike, a evoluirale zajedno?".