nonsense. west eurasian lineages and east eurasian lineages diverged 45,000 years ago. there were continued instances of gene flow. sub-saharan africans are 200,000 years apart. the distance halves every generation. it would take an additional eight generations to restore the same genetic affinity a person would have with another member of their ethnicity. even then your 7x great-grandchild that is 1/512 sub-saharan african wouldn't be on the eurasian cline. this doesn't take into account the admixtures with different archaic populations that widen the gulf even further. (neanderthal, denisovan, erectus, and a ghost population) it would take fewer generations to restore that genetic affinity if the child was half asian. even if the black american has a little bit of white heritage.
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