How to interpret this result
- This module uses your Ancestry Composition results to estimate the generation range where you are likely to have had a single relative who descended from a single population.
- These results may be helpful for learning about your genealogy, in figuring out from which ancestors a particular ancestry may have been inherited, or for piecing together the history of their likely migrations.
- For technical details on how this feature works, read our white paper.
This report predicts the ancestral origin of different parts of your DNA by comparing them to reference populations. By default, our confidence in a prediction must be greater than 50% to report it. Select a different confidence level to make your Ancestry Composition results more conservative. Read more about our ancestry analysis.
How we calculate your ancestral breakdown
To determine your ancestral breakdown, we use an algorithm that individually looks at short pieces of DNA across your genome. We compare each piece to DNA from reference populations from around the world, i.e. thousands of individuals with known ancestry. When a piece of your DNA resembles the DNA from a specific reference population with a high degree of confidence, it is assigned to that population. Sometimes a piece of DNA resembles reference DNA from several populations, in which case it is assigned to a "broad" ancestry (e.g. Northwestern European). If a piece of DNA does not closely resemble reference DNA from any populations, then that piece of DNA shows up in your results as Unassigned ancestry. These assignments are tallied across your genome to determine your final results. By default, your results are calculated at a 50% confidence level; you can see how your results change with different confidence levels in the Chromosome Painting section.
British & Irish
40.1%IrelandHighly Likely MatchUnited KingdomHighly Likely Match
French & German
Although we've detected French & German DNA in your ancestral breakdown, we have not identified more specific locations that your recent ancestors may have called home.AustriaNot DetectedBelgiumNot DetectedFranceNot DetectedGermanyNot DetectedLuxembourgNot DetectedNetherlandsNot DetectedSwitzerlandNot Detected
Although we've detected Scandinavian DNA in your ancestral breakdown, we have not identified more specific locations that your recent ancestors may have called home.DenmarkNot DetectedIcelandNot DetectedNorwayNot DetectedSwedenNot Detected
Although we've detected Iberian DNA in your ancestral breakdown, we have not identified more specific locations that your recent ancestors may have called home.PortugalNot DetectedSpainNot Detected
0.0%AlbaniaBosnia and HerzegovinaBulgariaCroatiaGreeceMacedoniaMoldovaMontenegroRomaniaSerbia
Broadly Northwestern European
Broadly Southern European
Although we've detected West African DNA in your ancestral breakdown, we have not identified more specific locations that your recent ancestors may have called home.Cabo VerdeNot DetectedCameroonNot DetectedGhanaNot DetectedGuineaNot DetectedLiberiaNot DetectedNigeriaNot Detected
Broadly Sub-Saharan African
Although we've detected Broadly Sub-Saharan African DNA in your ancestral breakdown, we have not identified more specific locations that your recent ancestors may have called home.KenyaNot DetectedRwandaNot Detected
Although we've detected Southeast Asian DNA in your ancestral breakdown, we have not identified more specific locations that your recent ancestors may have called home.American SamoaNot DetectedCambodiaNot DetectedGuamNot DetectedIndonesiaNot DetectedLaosNot DetectedMadagascarNot DetectedMalaysiaNot DetectedMyanmarNot DetectedNorthern Mariana IslandsNot DetectedPhilippinesNot DetectedSamoaNot DetectedThailandNot DetectedTongaNot DetectedVietnamNot Detected
0.0%North KoreaSouth Korea
Manchurian & Mongolian
0.0%ArgentinaArubaBelizeBoliviaBrazilChileColombiaCosta RicaCubaDominican RepublicEcuadorEl SalvadorGuatemalaHondurasMexicoNicaraguaPanamaParaguayPeruPuerto RicoUruguayVenezuela
Broadly East Asian
Broadly East Asian & Native American
Broadly South Asian
North African & Arabian
0.0%AlgeriaBahrainEgyptJordanKuwaitLibyaMoroccoSaudi ArabiaTunisiaUnited Arab EmiratesYemen
Broadly Western Asian & North African
There is a wide range of human diversity out there, and sometimes our algorithm can't pinpoint a region of your DNA to a specific population. Bear with us as our data and resources continue to expand. We expect the amount of unassigned ancestry our customers see to decrease.
East Asian and Native American
West Asian and North African
Understanding Ancestry Composition
How should I interpret my results?
In the DNA of all of us is a story, and that story is part of the broader human story. It’s a history of people migrating out of Africa and venturing out to populate the globe and build new cultures. Over millennia, as different groups of people separated from each other to move into new frontiers, small changes in our DNA occurred, leaving behind subtle clues about our history. Your Ancestry Composition report is a window into your story, and is powered by cutting-edge algorithms and data from diverse populations around the world.
At the heart of your Ancestry Composition report is your ancestral breakdown: a list of your population percentages arranged in a hierarchy of from the continental-level to more fine-scale, regional ancestries. For example: one person's DNA results may suggest 95% European ancestry, which can be further subdivided into smaller regional populations, like 60% British & Irish, 25% French & German, and 10% Scandinavian.
You may notice another layer of insights about the likely origins of more recent ancestors; these specific recent ancestor locations are listed just beneath each regional population percentage. Following the previous example, someone predicted to have 25% “French & German” ancestry may see specific recent ancestor locations where this “French & German” ancestry is common, such as Belgium or France.
The way we determine your recent ancestor locations (i.e. Belgium) is different from the way we calculate your ancestral background (i.e. 40% French & German). Instead, we use a separate algorithm to further refine your results. By way of example, if you have 40% French & German ancestry as well as a recent ancestor location result for Belgium, this does not necessarily mean that you have 40% Belgian ancestry – as you may still have German, French, Austrian, Dutch, or Swiss ancestry included in that 40% “French & German” result. We also report our confidence with which we assigned each recent ancestor result within the Scientific Details section. You can think of the confidence indicator as the probability that you have recent ancestry from a specific location; it doesn't necessarily provide information about how much recent ancestry is from that location.
Why do I have "Broadly" assigned or "Unassigned" ancestry?
Some pieces (or segments) of your DNA may resemble those of reference populations from multiple places around the world. For example, if a segment of your DNA matches reference DNA from many different European countries but not from outside of Europe, then we label your DNA "Broadly European." If a segment of your DNA matches a wide range of the Ancestry Composition populations (or it doesn't match any of them with high confidence), then we label it "Unassigned."
Broadly assigned ancestry can tell a different story about your genetic history than narrowly assigned ancestry. Your DNA segments with broadly assigned ancestry may match reference individuals from a relatively wide range of ancestral populations – possibly reflecting widespread migrations that occurred earlier than the timeframe for our Ancestry Composition algorithm. However, broadly assigned ancestries could also be capturing unique populations for which we don’t currently have data.
Our Ancestry Composition algorithm looks at short pieces of your DNA one by one. For each piece, it calculates the probability that the piece belongs to each of the different Ancestry Composition populations. When that probability is high for a single ancestry (or for one of the "Broadly" ancestry categories), we "assign" that ancestry to that piece of DNA. If none of the populations tested have a high probability (which can happen when an ancestry is not well described by our reference datasets), then that piece of DNA has Unassigned ancestry.
We are constantly working to improve our algorithm and collect more reference data. As the science continues to get better, we will be able to report on and distinguish more and more ancestry populations. Learn more about how we calculate your broadly and unassigned ancestries in our Ancestry Composition Guide.
I have 0.1% of an ancestry. What does that mean?
Small amounts of ancestry can mean different things for different people, and you may have to do some digging to learn what your trace ancestries (1% or less) mean for you.
We report Ancestry Composition results as small as 0.1% because our algorithm does a very good job estimating ancestry for each small piece of the genome. We believe that sharing your exact results allows you to get the most information — even though sometimes interpretation of those results isn't easy.
You can learn more by looking at your Chromosome Painting. Your 0.1% ancestry is more likely to reflect a real genetic history (and less likely to reflect random chance) if it is still assigned at the higher confidence levels. Another way to gain confidence in your ancestry estimate is to connect with close relatives and see whether their results also include small amounts of the same ancestry.
How long ago did I have an ancestor from this population?
There is randomness involved in how much DNA you receive from each of your ancestors, especially your ancestors from many generations back, so it's impossible to pinpoint this exactly.
Check out your Ancestry Timeline result for an estimate of when your most recent ancestor from each Ancestry Composition population lived, based on your genetics.
The technical details: chromosome recombination
Between every generation, our chromosomes recombine, meaning pieces of the chromosomes we inherited from mom swap places with pieces of the chromosomes we inherited from dad, and these new, mixed chromosomes are what we pass on to our children.
You will only pass on 50% of your DNA to each of your children, and – on average – 25% to each of your grandchildren. Continuing this pattern, by the time you are four generations removed (i.e. from a great-great-grandchild), you will only have passed on around 6.25% of your DNA. Similarly, by the time you are ten generations removed (i.e. from an 8th-great-grandchild), you will – on average – have passed on just 0.1% of your DNA. This percentage – 0.1% of your DNA – approaches the limits of the resolution of the Ancestry Composition algorithm, meaning we cannot easily distinguish smaller segments of your DNA. Also, while you may have DNA that you inherited from a distant ancestor, this inheritance becomes very "stochastic" around approximately seven to ten generations, meaning the presence or absence of DNA segments inherited from a distant ancestor is largely dependent on random chance.
I don't understand my Chromosome Painting.
Your Chromosome Painting is a visual depiction of the 23 pairs of chromosomes that make up your genome. Each chromosome is one long string of DNA — if you think of your genome as a book, the chromosomes are like the chapters.
You can see from the Chromosome Painting that your chromosomes come in pairs. Each pair of chromosomes is represented as a pair of colorful horizontal bars, labeled with numbers (1 through 22) or letters (X or Y) and colored by ancestry.
You inherited one of each pair of chromosomes from your mother, and the other from your father. Unless at least one of your parents is also a 23andMe customer, we can't tell which chromosomes you inherited from which parent. But if you connect with one or both of your parents, then your Chromosome Painting will update so that the top chromosome in each pair is the one you inherited from your mother, and the bottom chromosome is the one you inherited from your father.
Your Chromosome Painting contains a huge amount of information to explore. Take a look at this list of suggestions to get you started, or check out the blog post for even more information.
- The Chromosome Painting uses colors to show which pieces of your genome came from which of the 31 Ancestry Composition populations. You can hover your mouse over the different populations to highlight where they are found in your DNA.
- Talk with relatives or connect with them on 23andMe to compare which ancestries you have in common. If your parents are 23andMe customers, you can connect with them to learn which chromosomes you inherited from which parent. See the Frequently Asked Question, How can I learn more about my ancestry by connecting with family members? to learn more.
- The color of the DNA segments in your Chromosome Painting tells you about your Ancestry Composition, but the number and size of those segments is meaningful too. The shorter a segment is, and the fewer segments you have from one ancestry, the more generations since your most recent ancestor from that population.
- Change the confidence levels to see how they impact your Ancestry Composition. See the Frequently Asked Question, What do the different confidence thresholds mean? to learn more.
Why don't my Ancestry Composition results match what I know about my ancestry?
We have a high confidence in the accuracy of your results and the science behind them. But 23andMe is a genetic testing service, which means we can only show you what is found in your DNA. We recommend that you use your genetic reports together with your family history to build a complete understanding of your ancestry.
Why don’t I see an expected regional population percentage or recent ancestor location?
There are a few common reasons why your results might not match what you expect based on historical records or family stories:
- Some genetic populations are especially difficult to tell apart because they share common history. If you have genetic ancestry from one of these populations, it may be assigned to a broader category. For example, Italian ancestry may be classified as a combination of Italian and Broadly Southern European.
- Ancestry Composition populations are defined by genetically similar groups of people, not by the political borders of countries. In some cases, your ancestry may highlight the differences between population history and political history. For example, if you have ancestry from a part of France that is very close to the border with Spain, your DNA may be classified as Iberian (the population that includes Spanish ancestry) instead of French & German. In addition, if you are from a group within a country that is not common in our reference dataset or is very genetically similar to other countries for which we have larger sample sizes, it is less likely that you will get a match for that recent ancestor location.
- The time scale reflected by Ancestry Composition may be different from the time scale of your records. The reference datasets that we use to calculate your Ancestry Composition are designed to reflect distinct, genetically similar populations that existed before transcontinental travel and migration was common (~500 years ago). For example, if recent generations of your family lived in Latin America, you are likely to have some Native American and some Iberian genetic ancestry because most mixing between those two populations happened within the past 500 years.
- Countries are not all genetically distinct groups. For example, if you are from a group within a country that is not common in our reference dataset or is very genetically similar to other countries for which we have larger sample sizes, it is less likely that you will get a match for that recent ancestor location.
- Country borders have changed a lot even within the past 100 years, which can sometimes produce confusing recent ancestor location results. For example, country borders in Eastern Europe and the Balkans changed dramatically with the dissolution of the Soviet Union in the last decade of the 20th century.
I know I have Native American ancestry. Why doesn't it show up in my results?
Your results will include Native American ancestry if a piece of your DNA resembles our Native American reference panel. If your results do not include Native American ancestry, that does not necessarily mean that your understanding of your family heritage is incorrect.
Here are a few common reasons why you may not see the Native American ancestry in your results:
- If your most recent Native American ancestor was more than five generations ago, you may have inherited little or no DNA directly from them. The farther back in your history you look, the less likely you are to have inherited DNA directly from every single one of your ancestors. This means that you can be directly descended from a Native American without having any Native American DNA.
- Your Native American ancestry may be assigned to a “Broadly” category. Even using state-of-the-art science, the Native American and Northeast Asian populations are genetically similar, and sometimes they can't be distinguished from each other with high confidence.
- Throughout American history, people without a genetically Native American background have claimed Native American heritage for a variety of social reasons related to the shifting politics of race and indigeneity in the United States. As a result, many families without any genetically Native American ancestors have passed down stories about Native American ancestry. For examples, see this article or the book, Becoming Indian: The Struggle over Cherokee Identity in the Twenty-first Century, by Circe Strum.
Why don’t my Ancestry Composition results match the results I got from a different company?
While we are very confident in the way we calculate your results, we cannot make statements about the quality of your results from a different company. But if your results from 23andMe don't match the results you got from a different test, that could reflect differences in how we calculate your genetic ancestry.
Genetic ancestry calculations can disagree with each other for a few different reasons:
- Different companies rely on different reference datasets. The 23andMe reference datasets are made up of thousands of people with known ancestry, many of whom are 23andMe customers, and we use them to define our Ancestry Composition populations.
- As people migrate, the genetic patterns associated with a specific place can change over time. The 23andMe reference datasets were designed to reflect distinct global populations that existed before the widespread international travel and migration of the last 500 years.
- There are different ways to calculate your ancestry from your DNA. 23andMe uses an approach that involves phasing, which means we calculate your mom's and your dad's contribution to your ancestry separately.
- At 23andMe, we calculate your ancestry separately for small pieces of your genome one by one, using advanced machine-learning techniques. This piece-by-piece calculation creates powerfully informative results, including your Chromosome Painting and your Ancestry Timeline from each ancestry population, which contain a wealth of information to help you explore how you inherited your ancestry from your genealogical ancestors.
Why did my results change?
23andMe has offered customers a breakdown of their ancestry since 2008. A lot has happened since then – millions of individuals have joined our "gene pool" and ongoing research efforts have helped us understand more about genetic diversity around the world. We've also made great strides in improving the underlying algorithms that we use to deliver these results. In 2008, we broke down ancestry into three main categories: African, European, and East Asian. Since then we've offered a series of updates where we refined those original estimates into more and more granular results.
When we update the reference populations or the algorithms used to predict your ancestry, your results are expected to change. We have thus become accustomed to calling Ancestry Composition a living analysis of your DNA. For the most part, these changes should be minor and hopefully provide you with more detail about your ancestral origins. Sometimes these changes affect your regional population percentages, and sometimes they affect recent ancestor locations (the countries and territories sometimes listed beneath your percentages). Each time we make an update we update the "Change Log", which can be found at the bottom of the Scientific Details page.
Note that there are other reasons why your results can change. If you connect with one or both parents, we are able to further refine your results. See How can I learn more about my ancestry by connecting with family members?
Why did my recent ancestor locations change?
The reference populations we use to calculate your recent ancestor locations (the countries or territories listed underneath your regional population percentages) are updated on a frequent basis to include new reference individuals, so you may see your recent ancestor locations change as the size of our database grows. We are also constantly working to improve this calculation in a way that is more precisely calibrated to each location.
Want even more detail about how we estimate your ancestry? Check out our Ancestry Composition Guide.
Why is my Ancestry Composition different from my sibling's?
Even though you have the same parents, you and your sibling only share about half of your DNA. Your Ancestry Composition may be different in the half of your genome that you don't share.
Why does it work that way? For simplicity, let's focus on your mother. You inherited half of your mother's DNA, and your sibling also inherited half of your mother's DNA. But which half you inherited is the result of random chance because of a process called recombination. Through your mother, maybe you inherited a little more of your DNA from your maternal grandmother, and a little less from your maternal grandfather. Maybe for your sibling, it was the other way around. If your maternal grandmother and grandfather had different genetic ancestries, then your Ancestry Composition would be closer to your grandmother's, and your sibling's Ancestry Composition would look more like your grandfather's.
The science behind Ancestry Composition
How do you determine my ancestry? Do you use other information, or just my DNA?
We determine your Ancestry Composition using only the information in your DNA and the DNA of other people with known genetic ancestries (our reference datasets). Your 23andMe reports are always based on your genetics. If your results describe you perfectly, that just goes to show you how much your DNA really tells about you!
The technical details: regional population percentages
The 23andMe Ancestry Composition algorithm looks at short, non-overlapping pieces of your DNA, one by one. We compare each piece of your DNA to reference DNA from populations around the world. When a piece of your DNA matches the reference DNA from a specific ancestry population with a high degree of confidence, your DNA is assigned to that population. The results of these assignments are added up across your genome to calculate your overall Ancestry Composition.
Want to learn more about the science behind 23andMe Ancestry Composition? Check out our Ancestry Composition Guide.
The technical details: recent ancestor locations
Recent ancestor locations – like Belgium, Brazil, or Bangladesh – relate to the amount of DNA you share with people who have roots in that location (these people are called “reference individuals”). So, the more DNA you share with reference individuals from specific locations, the higher the likelihood is that those locations will be assigned to you. On average, people from a smaller, more homogenous country like Iceland will share more DNA than people who come from a larger, more diverse country like China. Because of population differences like these, we add a calibration step when determining our confidence for each recent ancestor location assignment.
Why do we ask you questions about your ancestry?
We never use your survey answers to produce your ancestry results. So why do we ask questions about your ancestry? Because you can tell us more about yourself than we can learn just by looking at your DNA alone. We use your self-reported ancestry for the following purposes:
- For customers who receive Health reports, we ask questions about ancestry and ethnicity to personalize results as much as possible. We use your self-reported ethnicity to calculate your post-test risk in Carrier Status reports and to show a “typical” result for comparison in your Traits reports.
- 23andMe customers also have the opportunity to participate in ancestry surveys. We use the results of these surveys to improve ancestry features that 23andMe customers know and love.
- We also use survey results from customers who have consented to research to advance genetic science through research studies. For example, check out this 23andMe publication about 23andMe research participants in the US who self-identify as African American, Latino, and European.
Why can't you provide more specific insights about my ancestry?
Ancestry Composition is designed to distinguish between as many populations as possible, but we only include specific ancestries if we can distinguish between them with high accuracy. Some genetic ancestries are inherently difficult to tell apart because the people in those regions mixed throughout history or have shared history. As we continue to collect collect more reference data and refine our algorithms, we will update Ancestry Composition vto include new populations.
In addition, the reference populations we use to calculate your recent ancestor locations are updated on a regular basis to include new individuals, so you may see new recent ancestor locations as the size of our database increases.
We determined your Ancestry Composition results based on genetic information that originated from a genotyping chip. Over the past decade, the quality of these chips has improved as new versions were released. Ancestry Composition is finely tuned to specific genotyping chip versions and sometimes new updates results are released on the newest version first before older versions.
In some cases, we don’t have enough data to tell different populations apart. As we collect more reference data, more specific ancestries will become easier to distinguish, and we will be able to report on more Ancestry Composition populations.
Because the majority of 23andMe customers are US residents with European ancestry, we have a lot of reference data from European populations, and we are able to distinguish more sub-populations from Europe as in any other continent. The 23andMe Research team is constantly working to get new data from diverse populations and to maximize the number of ancestries we can distinguish.
Historically, biomedical research has disproportionately included participants of European descent. Our mission at 23andMe is to help people access, understand, and benefit from the human genome. The best way we can do that for underserved populations is to include their genetic data in our research and our features. As we gain more diverse 23andMe customers through initiatives like the African Genetics Project, their genetic information will help to improve features like Ancestry Composition.
How do you determine my Ancestry Timeline?
Your Ancestry Timeline shows an estimate of when your most recent ancestor from each Ancestry Composition population lived. We use several pieces of information to calculate your Ancestry Timeline, including the number of DNA segments you have from each ancestry, the length of those segments, and the number of chromosomes they are found on. If your most recent ancestor from a population was very recent, you will have more segments of that ancestry on more chromosomes, and those segments will be longer, than if your most recent ancestor was many generations ago.
What is recombination?
Every time DNA is passed from one generation to another, the two chromosomes in each pair are randomly shuffled with each other in a process called recombination. This process can break up long segments of a single ancestry into shorter segments. Sometimes very short segments of ancestry are lost during recombination and don’t get passed to the next generation. This is why ancestry from your distant ancestors only shows up in a few short segments, if at all.
Why do I have a population in my Ancestry Composition that is not in my Ancestry Timeline?
Your Ancestry Timeline only shows narrow ancestries, which are not broken down into more specific ancestries. The broad, regional and continent-level ancestry populations and Broadly Assigned ancestries are not included in your Ancestry Timeline.
Additionally, your Ancestry Timeline is calculated using the ancestry segments on your 22 autosomal chromosomes. Ancestry populations that are only found on your X chromosome are not included in your Ancestry Timeline. This is because the X chromosome has a more complicated process of inheritance and recombination than the autosomal chromosomes, so it can't be analyzed in the same way. To see which segments of your ancestry are found on which of your chromosomes, check out your Chromosome Painting.
Getting more out of Ancestry Composition
How can I learn more about my ancestry by connecting with family members?
If you have a biological parent who is also a 23andMe customer, you can improve your Ancestry Composition report by connecting with them through the Share and Compare tool. For more information about connecting, see the How sharing works information page.
If you and your parent or child have profiles under the same 23andMe account, then your profiles will be connected automatically, and you won’t have to connect manually through Share and Compare.
How will my Ancestry Composition change if I connect with a parent?
When you connect with a biological parent through the Share and Compare tool, your Ancestry Composition will receive the following updates:
- We will use the additional information we learn from your parents' DNA to improve the resolution of your Ancestry Composition, so you may see slight changes in your Ancestry Composition results.
- If you connect with one or both of your parents, Ancestry Composition determines which parts of your DNA you inherited from each parent. Your Chromosome Painting will update so that the top chromosome in each pair is the one you inherited from your mother, and the bottom chromosome is the one you inherited from your father.
- If you connect with one or both of your parents, the Parental Inheritance section in your Ancestry Composition report will become active. You will be able to see the proportions of each ancestry that you inherited from each parent.
- Note: Connecting with a child does not change the Ancestry Composition results for parents.
To learn more about how your Ancestry Composition changes when you connect with a parent, read our article on The Phasing Process.
For more information about the algorithm powering the Ancestry Composition report and why connecting with close family members improves the resolution of your Ancestry Composition result, check out the Ancestry Composition Guide.
What do the different confidence thresholds mean?
Our algorithms make ancestry estimates based on probabilities and they’re generally very accurate, but your results are not set in stone. We are always trying to improve and refine these estimates. Therefore, we’ve included ways for you to explore your results at different levels of scientific certainty (i.e. “confidence”), and get more from them.
The algorithm we use to calculate your ancestral breakdown analyzes one small piece of your DNA at a time. For each piece of your DNA, we calculate the probability of that piece matching each reference population. By default, your results are calculated at a 50% confidence level; you can explore your results at different confidence levels by clicking the “Change confidence level” link in the Chromosome Painting section of the report.
Similarly, the algorithm we use to calculate your recent ancestor locations looks for pieces of DNA you share with individuals from around the world. Based on how much DNA you share and which country or territory is being considered, we assign a confidence to our prediction. We report these confidence levels in the Scientific Details section as “not detected,” “possible,” “likely,” or “highly likely.” “Possible” means we are between 50% - 59.9% confident in the assignment, while “highly likely” means we are at least 80% confident in the assignment. “Not detected” means we are less than 50% confident in assigning that recent ancestor location to you.
Let’s consider an example: Suppose there is a piece of DNA that is found in both Balkan and Italian populations, but it’s more common in Italy. If you have this piece of DNA, our algorithm might estimate that it has a 75% chance of reflecting Italian ancestry and a 20% chance of reflecting Balkan ancestry. If you set the confidence slider to 70%, then that piece of DNA will be labeled as Italian, because our 75% Italian estimate is greater than the 70% confidence threshold.
But if you set the confidence slider to 80%, the piece of DNA won’t be labeled as Italian because 80% is higher than the 75% Italian estimate. Instead, that piece of DNA will be labeled as Broadly Southern European, as there is a 75% chance of being Italian plus a 20% chance of being Balkan, which equals 95% chance of being Broadly Southern European. This example also shows why you are likely to see more "Broadly" or "Unassigned" ancestry in the Conservative View than in the Speculative View.
Does this mean you’re not confident in my Ancestry Composition if I set the slider to "Speculative"?
The short answer is no. We are confident in all of the results we provide, and we include the confidence slider to give you as much information about your ancestry as possible. The different views can be helpful in different ways, depending on what kind of information you’re looking for. You may also learn from how the painting changes when you change the slider.
The long answer is more complicated. We strive to push the cutting edge of genetic science so that we can share as much information with you as possible. And at the cutting edge of any scientific field, it’s usually impossible to say anything with 100% certainty. Instead, scientists talk about probabilities and uncertainty. It is impossible to paint your chromosomes with 100% certainty, but we give you the opportunity to explore how your Ancestry Composition looks across the range from 50% certainty to 90% certainty.
Recent Ancestor Locations
In order to be assigned a recent ancestor location, you must share identical DNA segments of at least 7 centiMorgans (a centiMorgan is the common measure of genetic distance) with five or more people with known ancestry from that location. Importantly, we don’t include close relatives (i.e. first cousins or closer) in this calculation, and these matching DNA segments must be unique, meaning we do not double-count identical segments you might share with multiple distant relatives. These initial steps determine the percent genome shared between you and the reference individuals for each location.
Next, we do a calibration step to set more meaningful thresholds that accounts for the special demographic histories of each location. This step looks at average amounts of DNA shared between positive controls (people who come from the same place: i.e. from Belgium) and compares that amount to the average amount of DNA shared between positive and negative controls (i.e. people from Belgium vs. people who aren’t from Belgium). We then use this comparison to set unique confidence thresholds for each location.