An Eurasian origin?
Ordinarily, I have zero interest in mitochondrial and NRY DNA studies, but there is an underlying issue here that is relevant to the important autosomal DNA - some of what has been considered "admixture" may not be, it may be due to a misunderstanding of haplotype/haplogroup origins or, for autosomal DNA, a lack of proper parental populations (or a lack of application of statistical significance). Or, a failure to go back far enough. That may or not be the case here, but in population genetics, as in science as a whole, there is never a "final answer" - new data should can always alter beliefs/hypotheses.
In any case, the "racial purity" meme is less relevant to EGI than is genetic kinship, an all-encompassing concept that takes into account all sources of genetic divergence (including real admixture), to establish the genetic benefits and costs of different biopolitical scenarios.