DNA ancestry kits promise to unlock the secrets of your heritage, telling you what percentage of your lineage comes from Africa, or Western Europe, or the Pacific Islands, for example.

But a recent CBC investigation found that when two identical twins in Canada sent their samples in to five popular DNA ancestry kits, the results were not, well, identical.

To learn why that happened, KCBS Anchor Melissa Culross spoke with Dr. Mark Gerstein, a Professor of Biomedical Informatics at Yale University whose lab independently analyzed the twins' results.