Meet Your Chromosome Painting

Editor’s note: The images in this post have been updated after Sarah’s results were phased against her parents.

Sarah Laskey, 23andMe Product Scientist
The Chromosome Painting is one of my favorite parts of the 23andMe experience because it is packed with information. Then again, it can also be a little intimidating because it shows so much all at once. In this blog post, I’ll walk through some basics of what your Chromosome Painting shows and what kinds of stories it can tell you about your genetic ancestry.

What is a Chromosome Painting?
Your Chromosome Painting is another way of looking at your Ancestry Composition results. It shows a colorful representation of the 23 pairs of chromosomes that make up your genome. Here is a photo of what real human chromosomes look like under a microscope, side by side with my Chromosome Painting:

1_karyotype

In the microscope photograph on the left, the chromosomes are laid out vertically; in the Chromosome Painting on the right, they’re shown as colorful horizontal bars. In both images, the chromosomes are shown in pairs and labeled with numbers (1 through 22) or the letters X and Y. My Chromosome Painting has two copies of the X chromosome because I’m female. The picture on the left shows the genome of a biological male, who has one copy of the X chromosome and one copy of the Y chromosome. Y chromosomes aren’t shown in Chromosome Paintings.

In the Chromosome Painting, gray regions in chromosomes 13, 14, 15, 21, and 22 represent parts of the genome where 23andMe doesn’t test any markers because the DNA sequences in those regions are repetitive and hard to measure.

Exploring your genetic ancestry
In your Chromosome Painting, your genome is “painted” with colors representing up to 31 different ancestries. You can hover over or click on the different ancestries in your Chromosome Painting to learn where they’re found in your genome.

The 31 Ancestry Composition populations are organized in a hierarchy, which reflects the genetic structure of global populations. For example, Britain and Ireland are part of Northwest Europe, which is part of Europe. To see this hierarchy in action, take a closer look at my Chromosome Painting:

2_painting

 

My Chromosome Painting shows genetic ancestry from several different fine-resolution populations like British & Irish, French & German, and Ashkenazi Jewish. But these are all sub-categories of European. When I click “European” on the right hand sidebar, my whole genome is colored in “European blue”:

3_european

What can you do with your own high-resolution picture of the Ancestry Composition on each of your chromosomes? You can click on the different populations to understand how they relate to each other and where they’re found in your genome. You also can talk to family members (or connect with them on 23andMe) to learn which branches of your family contributed which parts of your genetic ancestry.

One segment, two segment, red segment, blue segment
The colors in your Chromosome Painting tell you about your Ancestry Composition, but you can learn even more by looking at the number and length of the DNA segments assigned to each ancestry. Everyone inherits half of their DNA from their mother and half from their father. When DNA is passed from parents to their children, the two chromosomes in each pair are randomly shuffled together in a process called recombination. This process breaks 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 of your genome, if at all.

The technical term for the genetic mixing of previously separate populations is admixture. If you have different DNA segments painted with different colors in your Chromosome Painting, those are evidence of admixture in your genetic history. Take a look at these two Chromosome Paintings side by side:

4_sarah_antonio

These Chromosome Paintings show very different genetic histories, and not just because of their Ancestry Compositions! Even if we ignore the colors themselves, the two pictures are pretty different. The long, unbroken stretches of color on the left are evidence of recent admixture, while the short segments of different ancestries on the right suggest admixture many generations ago.

My Chromosome Painting is the one on the left. I have one grandparent whose family came from Germany, one grandparent whose family came from Ireland, and two Ashkenazi Jewish grandparents. In other words, my ancestors from different European populations just started mixing together in the past two or three generations. The Chromosome painting on the right shows someone who identifies as Latino (Antonio, an Engineer at 23andMe), whose Native American (yellow), African (pink) and European (blue) ancestors probably started mixing with each other many generations ago.

How can you use this information to understand your own Chromosome Painting? In general, if your most recent ancestor from a population was very recent, you will have segments of that ancestry on more chromosomes, and those segments will be longer, than if your most recent ancestor was many generations ago.

Thanks, Mom and Dad!
If you have a biological parent or child who is also a 23andMe user, you can connect with them to improve the resolution of your Ancestry Composition results. Connecting with a parent will also reorganize your Chromosome Painting 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.

Even if you are not connected with either of your parents through 23andMe, you may still be able to learn a little bit about their ancestry by looking at your own Chromosome Painting:

If you are male, you inherited all of the ancestry painted on your X chromosome from your mother.

If you have the same ancestry painted in the same place on both copies of a chromosome, then you inherited the same ancestry from both of your parents in that region of your genome.

If you share a segment of DNA with a DNA Relative, and you know whether you are connected to that relative on your maternal or your paternal side, then you inherited that segment of DNA (and its ancestry) from the same side of your family through which you’re connected to that relative.

If your parents come from different genetic backgrounds, then you may be able to guess which chromosomes you inherited from which of your parents just by looking at the ancestries painted on each chromosome. For technical reasons, this will work even better if you are connected with a parent because our computational algorithm will be able to phase your raw data with more accuracy.

A deeper dive: Confidence levels
If you’ve mastered the basic details of your Chromosome Painting and you’d like to explore at an even more advanced level, click on “Change confidence level” and move the slider that appears above your Chromosome Painting. You can explore the different views of your Chromosome Painting at different confidence levels, and you can also compare those different views to each other.

5_confidence_1

The algorithm we use to calculate your Ancestry Composition analyzes one small piece of your DNA at a time. For each piece of your DNA, we calculate the probability of that piece coming from 31 different populations. The confidence slider on the Chromosome Painting allows you to explore our estimates of your genetic ancestry at different probability cutoffs. For example, if a segment of your DNA has a 55 percent chance of being Japanese, then that segment will be painted as Japanese at the 50 percent confidence level, but it will be painted with a more broad ancestry (either Broadly East Asian, Broadly East Asian & Native American, or Unassigned) at the 60 to 90 percent confidence levels.

Putting it all together
Everyone’s genetic history is a little different, so every Chromosome Painting has a different story to tell. This means that you may learn more about your ancestry from some of the suggestions in this blog post than from others. Just remember — like every true work of art, your Chromosome Painting isn’t something to be understood, but something to be explored.

For a detailed technical explanation of how we calculate your ancestry and paint your chromosomes, check out the Ancestry Composition Guide.






  • Cathy Matters

    DNA is rather confusing to the layperson. I am trying to locate my father. I thought 23andme would be ideal (my relatives recommenced you to me). Than I find out that I cannot locate any relatives on my fathers side….unless I have DNA from a male relative on my paternal side. I do not know who my father is, so how can I expect to locate him via male relatives on his side for a DNA match!?

    • 23blog

      Hi Cathy,
      That’s not accurate. You will indeed be matched with relatives on both sides of your family tree. The issue is that it may be difficult to figure out which of these matches came from your mother and which came from your father. In your circumstance there are some ways to triangulate that information without having a male relative on your paternal side testing. If, for example, there is a distinct ancestry difference between your mother and father, and you know what one of their ancestries are you can look at your matches draw some conclusions about which side a relative is based on that ancestry. If you have any surnames or geographic information about your paternal side, you can group your matches based on that, for example. But to reiterate your results — the DNA relative matches, as well as your ancestry composition — includes contributions from both your mother and father. Here is a link explain the differences in results between men and women: https://customercare.23andme.com/hc/en-us/articles/202908000-Do-men-and-women-receive-different-ancestry-information-from-23andMe-

  • 23blog

    Hi Cathy,
    It can be hard sorting through your matches. You are at a tough stage in the process as well. Another thing you might look at is the “relatives in common” view. So if you have a few closer matches, click on them and if you are sharing then you can see the information that you have in common as well as relatives in common. You can also turn to the community forums for help either with specific questions about your matches and we’ve heard from many customers who have turned to “Search Angels” who help them sort through their results and other records in search of biological relatives: http://dnaadoption.com/index.php?page=search-angels

  • Celina G

    My dad passed. I got my brother to do 23and me. How do I tie his DNA to mine, so that I can see the paternal results of my DNA?

  • 23blog

    Hi Kent,
    Without getting too technical what you are interested in is whether you have somatic mutations. These are changes that occur during your lifetime due to environmental exposures or cancers, for instance. What 23andMe looks at when we genotype a customer are germline mutations, variations in the genotype that are passed from one generation to the next. Just as with somatic mutations these changes sometimes influence traits, disease risk and other characteristics.

    • Kent M

      oh well.

  • 23blog

    Hi Catherine,
    I would suggest that you periodically check back for matches. We have thousands of people joining every day so the odds for you finding closer matches are quite high.

  • Cindy Jo Romano McGraw

    hang in here Catherine. I have been having mofe and more relatives showing up each week, as more and more complete their own DNA testing. Make sure you have your report cross posted to other sites which allow it, to gain better exposure for matches, too.

  • herlanda1

    Since you are already here, you should take advantage of the free site GEDmatch.com, which combines information from several testing companies including 23andme.
    More and more are having their DNA tested. I’ve been here for several years now and new people and advances in technowledgie are bringing results. Keep checking back and continue to inform yourself to the various sections on this site.

  • I am a Painter, and I object to the term “Chromosome Painting”.
    My degree is MFA; and I’ve been painting for over 40 years… and painting is not, as far as I’m concerned, a hobby. It seems so distasteful to have your life’s work treated as a hobby! I also do graphics for a living, and while I appreciate Infographics to explain phenomena, it is nothing like being a Painter. Visually, it is informational, but can you find another term to describe this? Chromosome Graphics, maybe?

    • Josh B.

      Nancy, 23 and Me didn’t create the term; Geneticists did. https://www.ncbi.nlm.nih.gov/mesh/68020223
      But I get it. I am a nurse and I hate it when a waiter says that she will “be taking care of me tonight.”

      • ExplosiveJim

        Are they not going to be taking care of you while you are there?

  • roland von freiser

    How is it possible for 23andme results to broadly state that an individual is 25 percent “broadly” European or Middle eastern. And yet they apparently can pinpoint a specific region?group at <.1 percent? I don't understand how this is possible.

    • Depths Of My Soul!

      To my understanding broadly means you share similar genetics with populations who have mixed with other populations within close proximaty and it is hard to distinguish between said populations or 23and me refuses to break it down where as your 1% probably has a higher confidence level of being a match to a distinguished population, possibly a less mixed population.

      Anyone can correct me if I am wrong

  • marialeonora

    that’s awesome! ive been trying to find my biological father too. I got a match to a second cousin 2.4% shared. but I don’t understand what this all means .please help

  • 1bestdog

    Please explain how I have .1 per cent Native American and the same for African yet am then told I had ancestors who were 100 per cent of each living between 1680 and 1800??? Would that not give me at least 1 or 2 percent of each?

    As well, how could I be 2-3 per cent Neanderthal if that ancestor has been 40,000 years ago, and is that factored in this total?

  • UpYourHorse

    Catherine, Your chances for finding a more closely related individual increase if you test with all the services available: Ancestry, 23andme, FamilyTreeDNA, and be sure to upload them at gedmatch.com to catch all the strays. Good luck!

  • 23blog

    Hi Audrey,
    If you are trying to see from which parent your French/German ancestry came from — this is the split view option — you
    can connect a parent on 23andMe to see what ancestries you inherited from each parent. There’s more detail on this feature here: https://customercare.23andme.com/hc/en-us/articles/212179688-Seeing-what-ancestry-you-inherited-from-each-parent

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