Japanese and European Roots
A boy with a European mother and a Japanese father was tested by his parents. His Y-chromosome was, not surprisingly, typically Japanese—haplogroup O-CTS10145, which is common in Japan. His mtDNA was also, as expected, typically European—H2a2. His autosomal results, presented in the “Who Am I?” section of his Genographic results, also reveal his mixed ancestry. He is 34% northeast Asian, 13% southeast Asian, and 2% Native American, all of which are typical of Japanese, northern Chinese, and Mongolian populations.
The 2% Native American actually reflects the fact that the ancestors of today’s Native Americans came from Asia, and reveals that there are still genetic patterns that they share from thousands of years ago. The ratio of his components is typically seen in our Chinese reference population, so this is reported as one of his closest populations. It is possible that some of his father’s ancestors might have come from China, so this is consistent with what we know about his genealogy.
While his East Asian components account for half of his autosomal ancestry, the other half is typically European: 22% northern European, 18% Mediterranean, and 10% southwest Asian. This pattern is typically seen in our German reference population, and so his other closest population is reported as German. His mother’s ancestors come from Germany and the UK, so this is again consistent with the known genealogy. Not bad for a DNA test!
Finally, he is 1.4% Neanderthal, which is lower than the average (approximately 2.1%) for non-Africans. Also, his Denisovan percentage is 0%, so he doesn’t appear to have any ancestry from these enigmatic Neanderthal cousins.
A Great-Grandmother’s Legacy
Julie looks typically European when you meet her, but she has a more complex ancestry than most people suspect. Her great-grandmother was Filipino, and the rest of her ancestors were from a mix of European countries. Since we get half of our DNA from each parent, and they got half from each of their parents, and so on, the average contribution of her Filipino great-grandmother to Julie’s own DNA would be ½ x ½ x ½, which is 12.5%. This seems like a pretty small contribution, but the Geno 2.0 test was able to pick it up, and the “Who Am I?” section of her results report shows that she is 9% northeast Asian and 4% southeast Asian—a total of 12%—just as predicted by the calculation above. The ratio is also pretty typical for populations from southern China and the Philippines, so it looks like the test was able to infer Julie’s ancestry correctly.
The rest of Julie’s DNA tells the story of her European ancestors. She has typical southern European numbers: 41% Mediterranean, 26% northern European, and 17% southwest Asian. (Southern Europeans from places like Italy and Greece have high Mediterranean percentages, while northern Europeans have higher percentages of northern European components.)
Because of the complex mix of Julie’s ancestry, predicting the closest populations is tricky. The first, Sardinian, is consistent with her southern European ancestry. The other population, Tatar (Russia), reflects her 12% East Asian components that are found at similar levels in Russian Tatars, a group of people who moved to Russia from further east in Asia.
The way we calculate closest populations is improving as we learn more about global genetic patterns and how to analyze the data from the genotyping chip, but for now we choose the closest populations from our reference set on the basis of the predicted mix of the regional components; the mix that is closest to yours provides us with your two closest populations.
A Former Orphan Seeks Answers
Peter is adopted, and knows very little about his ancestry apart from that he was once in an orphanage in the northern part of Colombia. He has never been back to Columbia, and doesn’t know of any living relatives. The Geno 2.0 test is his only insight into his ancestry.
His Y-chromosome result, common to many people of Colombian ancestry, is western Eurasian—J-L147.1. It is most common in the Middle East and North Africa, and Peter may have ancestors who were among the Moors that invaded Spain in the 8th century. It’s also possible that his ancestors might have been Jewish, since many Jewish men also belong to this lineage. Either way, he clearly has some ancestry from Europe or the Middle East on his father’s side.
Peter’s mtDNA result reflects his South American heritage—A2w. A2 was one of the original lineages to enter the Americas from Siberia over 15,000 years ago, and today it is particularly widespread in South America. In fact, Juanita, the “Ice Maiden” discovered by National Geographic Explorer-in-Residence Johan Reinhard in Peru in 1995, belongs to this same haplogroup. This mix of Eurasian Y-chromosome and Native American mtDNA is common in Colombia.
Peter’s autosomal results as presented in the “Who Am I?” section of his report reveal even more complexity in his ancestry. He is 27% Mediterranean, 19% northern European, and 9% southwest Asian—a ratio of components typical of Mediterranean Europe, particularly Spain. He is also 23% Native American, consistent with his mtDNA result. And, surprisingly for him, he is 19% sub-Saharan African, something he wasn’t expecting. This is pretty common in Colombia, though: Many people from Africa were resettled during the slave-trading era in the 16th to 19th centuries, particularly in coastal areas that included northern Colombia, where Peter thinks he is from.
Consistent with this mixed heritage, Peter’s closest populations are other mixed groups from the New World—Puerto Ricans and Mexican-Americans—where similar migrations to those in Colombia played out over the past five centuries. Peter’s results reveal how complex genetic patterns can be in today’s world, and it has taught Peter far more about his ancestry than he ever thought he’d be able to discover.