Is is possible that the Laings were substantially more than 5% non-white? After all, look at their pictures. Well, we know that individuals who are 25% African in ancestry can "pass" as white. As an example, to the left is Maya Rowell, who is 1/4 black. If 5% non-white ancestry is the expectation for Afrikaners, and ~50% are 0-5, then there is a "long tail" which extends out into domains of substantial non-white ancestry. I suspect this is plausible because there was admixture as late as the 19th century, as opposed to 2,000 years ago as for the Uyghurs. After ~100 generations the ancestry should be approximately equally distributed across the population, but far less so on the order of 5-15 generations.