Dahm discrepancy

The basics of the test showed that the three girls were, in fact, all 99% European, according to their DNA. So far, so identical. What became strange, however, was when their DNA was broken down even further. For example, Erica was found to be 16% Irish and British, whereas Nicole was 2% MORE Irish and British. How could this be? The results continued to come in, confusing the triplets, The Doctors, and the audience.