Overview (All Genographic kits)
Your results are inferred about you from a very small sample of your DNA. The DNA sample you gave us is unique to you, coming from a mixture of the DNA from your two parents. Your parents inherited their DNA from your four grandparents, and their DNA came from your eight great-grandparents, and so forth and so on. In a way, you are the product of a chemical combination of all those people that came before you, and all of them are your ancestors.
In recent years, scientists have discovered that different parts of your DNA can tell us about historical and prehistorical events in your ancestral story. We can estimate when or where these events happened by looking for small variations between your DNA and that of other people around you. These small variations are called mutations. Mutations are usually rare and, in nearly all cases, occurred only once in the past. Therefore, any two people who share a rare mutation must have inherited it from a shared common ancestor. By counting your rare mutations and comparing them to those of thousands of other people, we can begin to construct your personal story.
Why do results about deep and regional ancestry differ (Geno 2.0 and later)?
Deep ancestry is based on either your mitochondrial DNA or your Y-chromosome DNA, and it shows only a single line of descent (either your direct maternal or paternal line). For men it shows both lines of descent, while for women it shows only the maternal, since women do not have a Y chromosome. In contrast, your regional ancestry is based on the mutations across all of your DNA and therefore shows the contribution from every one of your hundreds of ancestors.
Your Regional Ancestry Explained (Geno 2.0 and later)
We determine your recent ancestry by analyzing small bits of DNA scattered across your entire genome. This portion of your ancestry comes equally from both parents, all four grandparents, all eight great-grandparents, and so forth. Unlike mtDNA and Y-DNA (see Your Deep Ancestry Explained), this portion of your DNA gets scrambled every successive generation, so what we can learn from it is not so much your deep history, but instead events in historic time, and even events more closely linked to your known ancestors.
In this section of your results you’ll see a set of percentages that represents a rough estimate of how much DNA you share with various groups around the world. Humans originally evolved in Africa, and over time they left the continent and began to spread across Europe, Asia, and Australia. As time passed, people who were living in one region acquired new DNA mutations across their whole genome, and these mutations were specific to that region. The mutations eventually spread to become common across the regional population. Therefore, two ancient neighbors were more likely to share genetic patterns than two people living on opposite sides of the world, because their ancestors were more likely to have encountered each other and borne children. Over time, this has made people from Senegal, for instance, more similar genetically to each other than they are to people from China, and vice versa.
Migration has also served to disperse these regional population patterns over time. For instance, the spread of agriculture from the Middle East into Europe also dispersed Middle Eastern genetic patterns as these early agriculturists moved into Europe. This is why someone who is, say, Irish and Scottish on both sides of their family going back many generations would show Middle Eastern or Southern European components in their regional affiliations—not because their great-grandparents migrated from those parts of the world, but because over thousands of years, Europeans have mixed with people from these regions and have retained traces of this mixture in their DNA. For example, if you have 40 percent Eastern European DNA but also, say, 12 percent Southern Asian DNA, then sometime in the past, your Eastern European ancestors mixed with your Southern Asian ancestors, leaving a trace of both groups in your DNA.
Similarly, if your parents came from very different parts of the world—say Denmark and Japan—this would be more clearly reflected in your regional percentages, which is the percent of your DNA that you inherited from each region. Since you get half of your genome from your mother and half from you father, you would be half Danish and half Japanese. At your own genetic level, this would show up as half of the regional percentages that each of your parents had—Scandinavian, Central European, East Asian, and so on.
However, remember that the percentage of your DNA that comes from each of your ancestors drops by half as we go back through the generations—you inherited half of your genome from your mother and half from your father but only a quarter from each of your grandparents. Because of this, our ability to see your regional ancestry decreases with each preceding generation. If, say, your great-grandmother (three generations removed) was 100 percent Native American, that would show up as roughly 12 percent of your DNA. Our rough limit is six generations, or 64 ancestors, each of whose contribution is less than 2 percent of your DNA. Beyond that, we can’t be certain that the percentages are significant. For this reason, we don’t identify regional percentages that are less than 2 percent in your results, even when they do exist.
People with recent ancestry from different populations can have a mix of regions in their DNA that’s not typically seen in indigenous populations. Hispanics, for instance, will often have typical European as well as Native American and/or African components—a result of the mix of cultures and peoples that has occurred in the Americas over the past 500 years.
Modern-day populations around the world carry particular blends of regional affiliations. After calculating your regional percentages, we compared your DNA results to the averages from more than 50 modern reference populations we currently have in our database, and we estimated which of these groups were most similar to you in terms of the genetic markers you carry.
Notice some unusual populations listed for you? This doesn’t mean that you belong to these groups, only that these were the groups in our limited number of reference populations that were closest to you. As we expand our set of reference populations (Geno 2.0 Next Generation currently has 60 reference populations), you may find that you are closer to another group. This simply reflects the ongoing scientific refinement of the Genographic reference dataset, as well as improvements in our methodology for assessing your closest populations. Remember, the regional blends that show up in your regional ancestry were determined over thousands of years, so you may see surprising regional percentages reflected in these populations.
Your Deep Ancestry Explained (All Genographic kits)
We determine your deep ancestry through the analysis of two small and distinct segments of DNA known as mitochondrial and Y-chromosome DNA.
The Maternal Journey
Mitochondrial DNA (mtDNA) exists in every male and female alive today. It is a portion of DNA inherited strictly maternally. At conception the sperm that fertilizes the egg does not pass on any mtDNA—it comes purely from the ovum and therefore from your mother. So your mother got it from her mother, who got it from her mother, who got it from her mother, and so forth, forming a deep and direct branch of strictly maternal ancestry. Because mothers pass on their mtDNA to both sons and daughters, we are able to identify a maternal haplogroup for every Genographic participant.
The Paternal Journey
The Y chromosome, on the other hand, only exists in males: Each man inherited his Y chromosome from his father, who got it from his father, who got it from his father, and so forth, forming another deep branch of direct ancestry. However, since Y-chromosome DNA (Y-DNA) only exists in males, we are currently unable to identify a paternal haplogroup from a female’s DNA sample. Female participants eager to learn about the paternal part of their ancestry will need their father, paternal uncle, or a full male sibling to participate, in order to obtain that part of the story.
When you click on Deep Ancestry, you’re taken to a map showing the route that either your maternal or paternal ancestors followed from Africa to the end point of their journey several hundred to thousands of years ago. This journey through time and space begins with the marker for your oldest ancestor and moves forward through time, showing at each step the possible route taken by the ancestor living at that point. Each successive step on the map represents the migratory path of a group descendant from the previous group, eventually forming the complete path taken by your haplogroup, or your deep ancestral branch of the tree. Each haplogroup has a name expressed by alternating letters and numbers—like Q2, J1c, R1b1a, and so forth—or by a letter followed by your terminal mutation, like R-M222. Your terminal mutation is the most recently occurring mutation in your ancestral journey, for which we test in the lab. Y chromosome haplogroups are often identified by this terminal mutation.
In the Deep Ancestry section we have highlighted major migratory movements or events along the way. For some of these movements or events, we provide more information about that part of the journey, including approximately when and where it happened—and our best understanding of how.
The last step in the journey is illustrated by a heat map showing through shaded plots the percentage distribution of your haplogroup in more recent times (time ranges vary from hundreds to a few thousand years ago for different groups). This information, gathered from participants in the Genographic Project as well as from the scientific literature, helps build a more detailed picture of where migratory groups settled during more modern history, helping to bridge the knowledge gap between our regional and our deep ancestries.
Your Hominin Ancestry Explained (Geno 2.0 and later)
In recent years, scientists have determined that modern humans are not the only ancestors represented in our DNA. During your ancestors’ journey from our original African homeland, they might have mixed with ancient hominins who lived tens and even hundreds of thousands of years ago—our human cousins like the Neanderthals in Europe and Asia. Their distinct genetic markers are still with us today. This means that you may find you have a small percentage (between 0 to 2 percent) of Neanderthal ancestry, even though those ancient species have long since gone extinct.