Eric and Dora are fraternal twins (i. e. they must be biological siblings) and they took an ancestry DNA test from two separate companies. The results of one company suggest Eric has 10% Russian heritage while the other suggests he has 25% Russian ancestry. The percentage of Russian heritage was the only major inconsistency between his two tests. Dora's tests from both companies indicated she had less than 5% Russian ancestry. Explain why or how it is possible for biological siblings like Eric and Dora to have differing percentages of Russian heritage AND explain why Eric's two tests have wide variability in the calculated Russian ancestry.