Whose Y to Use? Paternal Ancestry for Ladies

Editor’s Note: This post does not reflect our current product offering. 23andMe’s ancestry product looks at the autosomes (chromosomes 1-22), the sex chromosomes (XY), and mitochondrial DNA (mtDNA). For more information about how results are different for men and women go here.

One of the most exciting parts of 23andMe’s Personal Genome Service™ is discovering your genetic ancestry. Suddenly your family tree has branches that reach back thousands of years into the prehistoric past.gus.jpg

At present, 23andMe customers can trace two branches of their genetic family tree – one that follows the all-female line on the maternal side (through mitochondrial DNA) and another the all-male line on the paternal side (through the Y chromosome).

Not all DNA is created equal, however: males have both mitochondrial DNA AND a Y chromosome, so they can trace both their maternal and paternal ancestry. Females, who have mitochondrial DNA but no Y chromosome, can trace only their maternal ancestry.

So how can females discover their paternal history? One solution is to ‘borrow’ the Y chromosome of her most immediate paternal ancestor – her father. A female can have her father send his own DNA sample to 23andMe, then examine his Y chromosome as a way of understanding his paternal ancestry and her own.

But what if a woman’s father can’t or won’t share his DNA? By sharing 23andMe accounts with the right male relative, a woman can still discover both her maternal and paternal ancestry.

So whose DNA can a female customer use, besides her father’s? It could be anyone who shares his Y chromosome – her brother, paternal uncle (father’s brother), or even paternal grandfather (father’s father). The chart below illustrates some of the possibilities in one woman’s family tree; male relatives who share her father’s Y chromosome are depicted in blue.

You may look at the chart and ask: Why not her son’s Y? After all, he’s a male relative, too. But even though a mother shares 50% of her genes with each of her children, only fathers pass Y chromosomes to their sons. So any examination of her son’s Y chromosome would yield not her father’s paternal history, but her husband’s.

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The woman whose family tree is shown here (“Me”) could determine her paternal ancestry using the Y chromosomes of males who are colored blue.






  • 23blog

    Mary,
    Your results, all your results, reflect the contributions from both your mother and your father. So your DNA Relative matches, the individuals in the database with whom you are related will reflect that. The difference for women is that they have no Y chromosome, so it is not easy to identify if your matches are on your maternal or paternal side. So you would to infer some of that information. So for example if your birth mother was of Italian ancestry, but your birth father had no Italian ancestry than it would be easier to figure out that the DNA Relative matches you get with Italian ancestry are more likely on your mother’s side. The others would more likely be on your father’s side. You can use other kinds of information that you might have, geographic locations, surnames, etc to help you in your search. Here’s a link to more information about this topic: https://customercare.23andme.com/hc/en-us/articles/202908000-Do-men-and-women-receive-different-ancestry-information-from-23andMe-

  • Heather George Fergurson

    Help! Just been matched to first female cousin. Her mother was an only child and her father had 2 brothers and 2 sisters. So would my dna be traced only through her 2 paternal aunts or could It come from her uncles possibly? Adopted, searching for birth bloodline. Tks, Heather

  • 23blog

    Right now we do not have a way to upload other services DNA data. If you tested you would be able to see your matches, including relatives you have in common with this half sister. If she tested you’d be able to see if she matches as a half sister (if she has opted in to relative finder). You of course will also have more information about your ancestry and your own relative matches. Hope that helps.

  • Diane Beam

    Hi Everyone. If a women gets a dna test and has no known paternal relatives, but, dna testing reveals male relatives with a paternal connection, then could it be said that relative is an autosomal paternal relative …is that correct?

  • 23blog

    If that male is on your paternal line, then yes. For instance, if he is the son of your father’s brother. If he is your father’s brother (your uncle.)

  • 23blog

    Hi Diane,
    Among those there are paternal relatives, so that may help you in your search.

  • 23blog

    Testing won’t identify your mother’s paternal line, but the DNA that your mother’s father contributed is part of you. This shows up in the autosomes, so you may find relatives from that part of your family tree, and the traits and ancestry contributions from your mom’s dad are part of your results.

  • 23blog

    Ciaran,
    23andMe report on your mitochondrial DNA as well as your autosomes and sex chromosomes. You would not need to get a yDNA test. You would get matches from all branches of your family tree.

  • Gretchen

    I think I understand the difficulty of finding the paternal line being a female and no males to search with. Would it help at all if my mother and I did a test and then we could sort of subtract what we find is different?

  • rdmickey

    My maternal and paternal lines cross many times over the last 400 years traced. I am kin to myself in many ways. I have claimed after decades of research that I do not have a tree with branches, but a main trunk. The closest crossing of the lines is that my mother’s great-grandmother and my father’s grandfather were brother and sister. Since I am a female, and the testing will follow the maternal line, will I not get the Y as well? I am curious if I should just forego any testing and beg my elderly father.

  • 23blog

    No you do not. Your results reflect all branches of your family tree. Your ancestry composition results include what you inherited from both your paternal and maternal side. But if you are a women, we cannot assign a paternal Haplogroup to you because haplogroup assignments are traced through the Y-chromosome DNA, which women do not inherit, the assignment is only available for males. You can learn more about this here: https://customercare.23andme.com/hc/en-us/articles/202908000-Do-men-and-women-receive-different-ancestry-information-from-23andMe-

  • 23blog

    You are matched to customers with whom you are related, but you do not necessarily get their actual names unless they are “public.” But if you are given a match, you can message them to see if they want to share family information. This gives customers the ability to control how much they want to share and when.

  • alexa r bruno

    My mother has passed away and I’m looking for any biological matches for her side of the family. If, I have myself and my daughter tested will that help with figuering out my mother’s maternal line or would it be better to also test my son?

    • 23blog

      Alexa,
      When you test you will be able to see matches on all branches of your family tree. Your maternal haplogroup will also be identified and you will be able to see which of your matches are on your maternal line. Although you will have matches on your paternal line, we cannot assign your paternal haplogroup because women do not inherit a Y chromosome so it may be harder to figure out which of your matches are on your paternal side.

  • 23blog

    Amanda,
    I’m sorry to hear about your father. You do indeed inherit 50 percent of your DNA from your mother and 50 percent from your dad. The results you get from 23andMe reflect that equal contribution from both your mother and father. This is reflected in the mix of ancestry, your traits, and the wellness reports. It’s also reflected in the relatives you are matched with through your DNA. The one caveat is that we cannot assign what is called a paternal haplogroup to women customers. This can be helpful information for people trying to identify which side of the family some of their DNA Relatives fall on. (Are they on your mother’s side or your father’s side?) And this is because women do not inherit a y chromosome from their fathers. Here is a link to explain this a bit more: https://customercare.23andme.com/hc/en-us/articles/202908000-Do-men-and-women-receive-different-ancestry-information-from-23andMe-

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