According to 23andMe’s findings, Charlsie has nearly 10 per cent less “broadly European” ancestry than Carly. She also has French and German ancestry (2.6 per cent) that her sister doesn’t share.

The identical twins also apparently have different degrees of Eastern European heritage — 28 per cent for Charlsie compared to 24.7 per cent for Carly. And while Carly’s Eastern European ancestry was linked to Poland, the country was listed as “not detected” in Charlsie’s results.

“The fact that they present different results for you and your sister, I find very mystifying,” said Dr. Mark Gerstein, a computational biologist at Yale University.