In genetics, a common Single Nucleotide Polymorphism indicates a common ancestor at some previous stage, however, it does not necessarily account for the full geographical distribution of that SNP over the course of previous generations. Over the course of generations, some related individuals, or populations, might pass away without having descendants.
It is otherwise unclear, when the present Chinese ethnicities arrived in China. Inasmuch as oriental facial morphology originated as an adaptation to extreme cold climates, it seems more likely that The late Pleistocene ancestors of the Chinese migrated to the temperate climate of China from an extreme northern region, perhaps not so far from where Native Americans originated in Siberia.
While Native Americans show many peculiar hereditary SNPs and genomes, The indigenous population of the Altai Mountains demonstrate several similar SNPs.