In honor of both Easter and Passover, we want to share Debra&#8217;s 23andMe story.
A Christian, Debra didn’t just read the Bible, she began to immerse herself in the Torah, the first five books of Hebrew Scriptures that are also part of the Old Testament. <img loading="lazy" decoding="async" class="alignright size-medium wp-image-20783" src="https://blog-api.23andme.com/wp-content/uploads/2014/04/Debra-Moore-Photo-200x300.jpg" alt="Debra Moore Photo" width="200" height="300" />In looking into her own family history she didn’t have her parents around anymore to ask about her ancestry so went to the DNA and tested with 23andMe.
What she didn’t know was that those two paths would cross in a most unexpected way.
A teacher by profession, Debra has always had an innate desire for knowledge. After going through a very difficult divorce she sought solace in the scripture.
“As a Christian, I wanted to understand and appreciate the Jewish roots of Christianity. So I began researching the Torah,” she said.
A three-year spiritual journey ensued. Debra delighted in the learning, immersing herself in the customs and celebrating the holidays.
“I remembered a preacher once saying, ‘If you want to be blessed, bless Israel.’” She said. “And here was this treasure of traditions that were unknown to me.”
Friends and colleagues would invite Debra for Passover and to break the fast on Yom Kippur. She celebrated Purim and Sukkot, joining in on the readings and embracing the customs.
“When my kids come home they know if it’s Friday we are going to have Sabbath prayers and they look forward to it,” she said.
As she continued on this spiritual journey, Debra took a personal journey as well when a few months ago her daughter suggested they both join 23andMe. Ever eager for discovery, Debra agreed. Waiting for the results was the hardest part.
“My daughter and I submitted our samples without acknowledging any family connection,” she said. “23andme recognized that we were close relatives and labeled her as my daughter. Wow!”
But the biggest revelation came when they both reviewed their ancestry results. They had tried other genealogy services in the past and were left with more questions than answers. This was not the case with 23andMe.
&#8220;I&#8217;ve known all my life I was African American – all I had to do was look in the mirror but this – this was so exciting. My most unexpected, but highly prized revelation was that we have Ashkenazi Jewish ancestry,” she said.
Debra was surprised and elated. After three years of immersing herself in the Jewish faith she now could say that was REALLY part of her. She immediately shared the news with the rest of her family, friends and colleagues.
“One of the secretaries who works with me is Jewish and we were always talking about the holidays and such. When I got my 23andMe results I ran down the stairs and I said “Look! We’re cousins!”
&#8220;It was such an honor to be in the room,&#8221; she said. &#8220;For four years, I had observed Passover at home alone, but this year, I stepped out and made contacts within the Jewish community. I am so thankful and grateful for 23andme.&#8221;
Through all of this Debra only has one regret, that her mother has passed and she was not able to share this news.
“Years ago, my mother worked with a man who was Jewish. She spoke highly of this man who worked along side her in a factory in St. Louis, MO and was not bothered that she was Black. She remembered that this man and his family were so kind to her.”
23andMe provides genetic testing services for informational purposes; your results may or may not help you to search for or identify relatives or family members.

23andMe Blog

23andMe Blog Team

We’re Cousins!

The ashes of the Holocaust left very little for Peter Istvan Kovacs to sift through in his search for his ancestors. 
<img loading="lazy" decoding="async" class="alignright size-medium wp-image-20406" src="https://blog-api.23andme.com/wp-content/uploads/2014/03/Peter-Kovacs-Photo-300x282.jpg" alt="OLYMPUS DIGITAL CAMERA" width="300" height="282" srcset="https://blogcms.23andme.com/wp-content/uploads/2014/03/Peter-Kovacs-Photo-300x282.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2014/03/Peter-Kovacs-Photo-768x722.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2014/03/Peter-Kovacs-Photo-880x828.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2014/03/Peter-Kovacs-Photo.jpg 991w" sizes="auto, (max-width: 300px) 100vw, 300px" /> 
There were very few Hungarian Jews who survived the war and exterminations. Among those murdered was Peter’s great grandfather, beaten to death in 1941 for refusing to convert to Christianity. Also lost to extermination camps and violence were innumerable relatives, he said.
<h6>“My grandmother had 11 brothers and sisters, and they all had many children,” he said. “We were a big family once.”Lost to War and Genocide</h6>
That family is gone now.
“I didn’t have any siblings and thought I had only two real cousins,” said Peter, who is a college student with an interest in anthropology and genetics. “We’re not a big family anymore.”
Wanting to know more about his ancestors Peter decided to get tested with 23andMe. He was interested in his ancestry and there just wasn’t anyone to ask.
“I’m interested in my roots,” he said.
<h6>Using DNA Testing to Explore Ancestry</h6>
Peter had heard about 23andMe and thought he might learn more about his ancestors.
On both his father’s and his mother’s side of the family, the war and Holocaust left very few survivors. It was much the same for all the Jews of Hungary, where the number of Jews before the war totaled about 6 percent of the country’s total population. After the war number of Jews there only amounted to about .1 percent of the total population.
For many people like Peter, who lost ancestors in the Holocaust it’s very difficult to piece together their family’s past. Over the years organizations have formed to help both survivors and their descendants piece together those missing pieces of their family history.
Those are important resources, but Peter also wanted to make connections using 23andMe.
“The day when I got my results has become a very important event for my life,” he said. “I just got a &#8220;family&#8221; back. At least that&#8217;s how I feel now and I&#8217;m so happy.”
<h6>Connecting to Cousins</h6>
He learned more about his ancestry, which includes both Sephardic and Ashkenazi Jewish roots.  And he found more than 1,000 23andMe DNA Relative matches – third and fourth cousins. More recently Peter found second cousins and one first cousin, using 23andMe. Those connections helped him find whole branches of his family that he didn’t know still existed. He was able to connect with many of his closest connections, learning that some of his relatives had escaped Hungary before and after the war, and immigrated to both Israel and the United States.
“They are very nice,” Peter said. “ Seeing their success and meeting them gives me new hope in life. And me who never had any siblings now has so many cousins.”
He also learned that one of his great grandfathers on his father’s side, Henrik RosenblÃ¼th, survived the death camps. Those relatives were able to fill him in on family history he would never have learned otherwise.
“It makes my heart warm. They survived,&#8221; Peter said. &#8221; I really cannot express my feelings, but it&#8217;s just beautiful.&#8221;
23andMe provides genetic testing services for informational purposes; your results may or may not help you to search for or identify relatives or family members.

Out Of The Ashes

When he was seven years old, Francisco Caravayo’s Puerto Rican grandmother told him a secret that he didn’t really grasp until decades later when he tested with 23andMe.
“I’m so grateful for the opportunity to finally have confirmation of my history,” Francisco said.<img loading="lazy" decoding="async" class="alignright wp-image-20313 size-medium" src="http://35.88.189.111/wp-content/uploads/2014/02/Francisco-Photo-1-248x300.jpg" alt="" width="248" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads/2014/02/Francisco-Photo-1-248x300.jpg 248w, https://blogcms.23andme.com/wp-content/uploads/2014/02/Francisco-Photo-1.jpg 411w" sizes="auto, (max-width: 248px) 100vw, 248px" />
<h6>Hidden Ancestry</h6>
When he tested with 23andMe, Francisco had wanted to contribute to research while exploring a little of his family’s Portuguese ancestry.
“My brother and I always felt as if there was a culture of secrets in our family,” said Francisco.  “When my grandmother said to all my cousins, ‘Never forget, you are of God’s chosen people,’ I knew what she meant, but didn’t understand why we couldn’t talk about it.”
In telling his story, Francisco goes back to his childhood, growing up in a Latino neighborhood. Most of his friends were Catholic, and although his family was  Lutheran and went to church regularly, something didn’t feel quite right to him.
“We went to church, but my father was always saying things like ‘Remember, Jesus was a Jew,’” Francisco said.
<h6>Conversos</h6>
After Francisco went away to college, he had a discussion one day with a Portuguese professor about his last name.  She told him that his surname was taken by Portuguese Jews many of whom had been forced to convert to Catholicism by the Inquisition, and many of these <img loading="lazy" decoding="async" class="alignright size-medium wp-image-20316" src="https://blog-api.23andme.com/wp-content/uploads/2014/02/Star-of-David-180x300.jpg" alt="Star of David" width="180" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads/2014/02/Star-of-David-180x300.jpg 180w, https://blogcms.23andme.com/wp-content/uploads/2014/02/Star-of-David-768x1280.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2014/02/Star-of-David-614x1024.jpg 614w, https://blogcms.23andme.com/wp-content/uploads/2014/02/Star-of-David-528x880.jpg 528w, https://blogcms.23andme.com/wp-content/uploads/2014/02/Star-of-David-708x1180.jpg 708w, https://blogcms.23andme.com/wp-content/uploads/2014/02/Star-of-David-scaled.jpg 1536w" sizes="auto, (max-width: 180px) 100vw, 180px" />
There were other clues.  His grandmother lit candles on Friday nights.  She taught the family that dairy and meat were not to be mixed and that shellfish were to be avoided.  Pork was eaten apologetically.  Christmas and Easter were not celebrated with joy, but with what can only be described as an obligation, as if performing a chore.  And when Francisco’s father died, Francisco followed family tradition: no clergy were present at the funeral and no Christian iconography was put on the gravestone.
<h6>Exploring His Jewish Ancestry</h6>
He began to explore his Portuguese roots and studying more about Judaism.  Shortly afterward, he saw an article in OUT Magazine about 23andMe’s research.  Francisco decided to get tested as a way to not just contribute to research, but also explore his own ancestry.
His results indicated Iberian ancestry, but also he saw that his paternal haplotype was shared by 20-to-30 percent of Sephardic Jews.
“That information was so grounding,” said Francisco. “I didn’t expect to find that I was 100 percent Jewish, because my ancestors tried to blend in and marry non-Jews, but I finally had evidence.”
He traced his haplogroup’s migration, and it matched up with the diaspora’s migratory patterns.  He was one of the thousands of families whose ancestors had escaped persecution by hiding their religion.
“I was sitting at the computer crying,” said Francisco
Not only did Francisco find answers to his past, but he also found a community of people on the 23andMe message boards that shared the same haplotype.  Through the online community, he’s been able to meet others like him and trade stories and information.
Francisco has now completed his conversion process to Judaism.  While he was going through the conversion, he met his current partner, who is Jewish too.
“I finally felt whole,” he said.

23andMe Helps Uncover Hidden Jewish Ancestry

<img loading="lazy" decoding="async" class="aligncenter wp-image-16833 size-full" title="23andMe-Uta-007" src="http://35.88.189.111/wp-content/uploads/2012/11/23andMe-Uta-007.jpg" alt="" width="508" height="726" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/11/23andMe-Uta-007.jpg 508w, https://blogcms.23andme.com/wp-content/uploads/2012/11/23andMe-Uta-007-210x300.jpg 210w" sizes="auto, (max-width: 508px) 100vw, 508px" />
 
We know from scientific research that, in general, people don’t freak out about the results they get from personal genetic testing. When the results show an increased risk for serious illness, how do they react?
It turns out that even then, the news doesn’t trigger serious anxiety. Quite the contrary, the results, according to a new <a href="https://peerj.com/articles/8" target="_blank" rel="noopener noreferrer">23andMe study published today</a> in the online academic journal <a href="https://PeerJ.com" target="_blank" rel="noopener noreferrer">PeerJ</a> found these test results prompted people to take positive steps, including talking to their doctors and discussing the results with family members who could also be at risk.
Lead author of the study and 23andMe’s Senior Medical Director, <a href="https://blog.23andme.com/news/23andmes-uta-francke-lauded-by-ashg/" target="_blank" rel="noopener noreferrer">Dr. Uta Francke </a>said the research addresses one of the most urgent questions in the field of genetics, “namely the impact of receiving unexpected information about high genetic risk for a life threatening disease.”
In this case, the study looked at how people reacted when they learned for the first time that they carried a mutation in either the BRCA1 or BRCA2 gene that put them at higher risk for breast and ovarian cancer.
Five to ten percent of breast cancers occur in women with a genetic predisposition for the disease, usually due to mutations in either the BRCA1 or BRCA2 gene. The mutations at the center of this study are responsible for a substantial number of hereditary breast and ovarian cancers among women with Ashkenazi Jewish ancestry.
The study found that those who acquired the potentially life-saving information not only took appropriate actions on their own behalf, but also notified relatives who might share that risk. In what the study described as a “cascade effect,” these relatives were tested because they were related to someone who had one of the high risk mutations.
A number of relatives who were subsequently tested discovered they too had one of the high risk mutations.
The findings are important given that a frequent criticism of direct-to-consumer testing is based on the assumption that it causes either serious emotional distress or triggers deleterious actions on the part of consumers.
Individuals who learned they had the mutation said they did not suffer serious emotional distress, and did not take inappropriate actions.
The study authors suggested that broader screening of Ashkenazi Jewish women for these three BRCA mutations should be considered.”

Customer response to direct-access BRCA genetic testing

<img loading="lazy" decoding="async" class="aligncenter wp-image-16670 size-full" title="Mayim's connections" src="http://35.88.189.111/wp-content/uploads/2012/10/Mayims-connections-e1674589980933.jpg" alt="" width="450" height="435" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/10/Mayims-connections-e1674589980933.jpg 450w, https://blogcms.23andme.com/wp-content/uploads/2012/10/Mayims-connections-e1674589980933-300x290.jpg 300w" sizes="auto, (max-width: 450px) 100vw, 450px" />
We plead guilty to occasionally geeking out on genetics, so it’s nice to see when someone else does it too.
In September, Moment Magazine got all nerdy and wrote about their<a href="http://www.momentmag.com/the-moment-magazine-great-dna-experiment/" target="_blank" rel="noopener noreferrer"> Great DNA Experiment</a>, in which they look at the 23andMe results of 15 notable Americans of Jewish ancestry and make some interesting genetic connections. It’s a good illustration of how our DNA can tell us about our interconnectedness.
The piece shows it’s not “six degrees” that separates these individuals from each other, but, in all but one case, no degrees of separation. This means that these individuals are all directly related to one another, albeit in most cases distantly. This was also news to the 15 participants.
All but one of the individuals has Ashkenazi Jewish ancestry. The one exception is Linda Chavez, the political commentator, who descended from Conversos, indivduals of Jewish and Muslim ancestry who converted to Catholicism during the Inquisition. Her ancestors eventually settled in New Mexico. But even in her case, although she isn’t directly related to any of the group, she is connected to each of the others individuals focused on in the piece by just one other individual in the 23andMe database.
The connections shown in the article are what prompted The New York Times columnist David Brooks and NPR “All Things Considered” host Robert Siegel to joke about learning they were distant cousins, sharing a common ancestor several generations back. Brooks kidded that he was “most surprised that our ancestors worked together on National Schetl Radio, on a program called ‘All Pogroms Considered.’” (Maybe the line needs a drum roll to work.)
The article shows the genetic connections between people like Mayim Bialik, the actress on the Big Bang Theory, and Stephen Dubner, co-author of Freakonomics. Or the connections between NPR’s Siegel, and Harvard Law professor, Alan Dershowitz, or his connections to 23andMe’s CEO’s mother Esther Wojcicki, a journalist and teacher. The magazine shows the connections and the amount of shared DNA, measured in centimorgans (cMs), to illustrate the “relatedness” of any two individuals. More closely related individuals share more DNA.
So why is all this interesting?
It is a very specific example of unexpected connectedness. We&#8217;ve written about this <a href="https://blog.23andme.com/news/make-that-three-degrees-of-separation/">interconnectedness before</a>. We’ve even seen unexpected connectedness <a href="https://blog.23andme.com/ancestry/23andmes-three-degrees-of-separation/">among 23andMe employees</a>. Even in cases with people who have vastly different backgrounds and experiences, one can use genetics to create a short chain of people to connect any two individuals to each other. A little geeky, yes, but pretty cool nonetheless.

Using 23andMe to Make Connections

<img loading="lazy" decoding="async" class="aligncenter wp-image-13198 size-full" title="whitebloodcell" src="http://35.88.189.111/wp-content/uploads/2012/05/whitebloodcell.jpg" alt="" width="350" height="260" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/05/whitebloodcell.jpg 350w, https://blogcms.23andme.com/wp-content/uploads/2012/05/whitebloodcell-300x223.jpg 300w" sizes="auto, (max-width: 350px) 100vw, 350px" />Crohn’s disease develops when the immune system mistakenly attacks the body’s own gut cells.
Although most people with European ancestry are pretty genetically similar, some sub-groups like Ashkenazi Jews have distinct genetic characteristics that carry important implications for health. For instance, people with <a href="https://blog.23andme.com/articles/detail-for-ashkenazi-ancestry">Ashkenazi ancestry</a> have higher rates of numerous rare genetic disorders like <a href="https://www.23andme.com/topics/carrier/tay-sachs-disease">Tay-Sachs disease</a> and are at increased risk for certain multi-gene conditions like Crohn’s disease.
The exact cause of Crohn’s disease isn’t known, but this inflammatory bowel disease may result from a case of mistaken identity – the immune system mounts a reaction to an invader and ends up attacking the body’s own cells, too. At least 12 genetic factors have been associated with Crohn’s disease in Europeans. Although researchers don’t know why people with Ashkenazi ancestry are two to four times more likely to develop Crohn’s disease, they suspect that the genetic “uniqueness” of this group may have something to do with it. 
 
To investigate this intriguing idea, a research team led by scientists at Columbia University and Mount Sinai carried out a study looking at nearly 2,000 people with Crohn’s disease and roughly 4,500 people without it, all of <a href="https://blog.23andme.com/articles/ashkenazi-ancestry-and-health">Ashkenazi descent</a>. The results, published in <a href="http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.1002559">PLoS Genetics</a> earlier this year, replicate previously reported associations for people of European descent and also identify novel factors specific to those with Ashkenazi ancestry.
In the new study by lead author Eimear Kenny, individuals with the C version of and the G version of had slightly higher odds of developing Crohn’s disease. Two other factors seemed to be protective. People with the T version of and the G version of had slightly lower odds of developing Crohn’s disease. More research is needed to understand how these genetic variants influence the biology of the disease.
These new findings confirm that genetics likely has something to do with the higher rates of Crohn’s disease in people with <a href="https://blog.23andme.com/articles/detail-for-ashkenazi-ancestry">Ashkenazi ancestry</a>. All of the newly discovered factors appeared to be specific to Ashkenazi ancestry as they weren’t found in previous studies carried out with broader European study groups.
May is Jewish American Heritage Month. Read about <a href="https://blog.23andme.com/?p=13178">the “uniqueness” of Ashkenazi Jewish ancestry</a> and how it’s important for health. Read more about Jewish ancestry in guest posts by 23andMe&#8217;s Ancestry Ambassadors, Tim Janzen,  CeCe Moore, and  Andrea Badger.

Genetic Factors for Crohn’s Identified for Ashkenazi Jewish Ancestry

As the series <a href="https://www.pbs.org/wnet/finding-your-roots/" target="_blank" rel="noopener noreferrer">Finding Your Roots with Henry Louis Gates, Jr.</a> begins its 10-week run on PBS, The Blog will feature posts from 23andMe’s Ancestry Ambassadors featuring their own stories about using DNA to dig into ancestry.
By Andrea Badger
<img loading="lazy" decoding="async" class="alignright size-medium wp-image-12315" title="Andrea's Tree" src="https://blog-api.23andme.com/wp-content/uploads/2012/04/Andreas-Tree-226x300.jpg" alt="" width="226" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/04/Andreas-Tree-226x300.jpg 226w, https://blogcms.23andme.com/wp-content/uploads/2012/04/Andreas-Tree.jpg 442w" sizes="auto, (max-width: 226px) 100vw, 226px" />
There has been a legend in my family, passed down from generation to generation, about my third great-grandfather Nathaniel Lewis. According to family folklore, his name wasn’t originally Nathaniel Lewis, but rather, Nathaniel Levi. As the story goes, our Lewis ancestors were Jewish people who converted to Christianity and changed their name from Levi to Lewis.
I had always wondered if this family story was really true. Everyone in our family has been told this legend but no one really had any conclusive evidence — just small clues. My grandmother and her siblings remember their mother singing Jewish songs to them as children. We also have an old newspaper article about our ancestor that states in passing ‘Nathaniel Lewis has lived in Scotland for many years but has no Scot’s blood’. Many of my relatives have speculated that this statement reveals that although Nathaniel was of Scottish nationality, he had a different ancestral background — Ashkenazi Jewish. However, conclusive evidence about this hypothesis was lacking until I joined 23andMe.

<img loading="lazy" decoding="async" class="alignright size-medium wp-image-12316" title="Andrea's Community Response" src="https://blog-api.23andme.com/wp-content/uploads/2012/04/Andreas-Community-Response-300x249.jpg" alt="" width="300" height="249" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/04/Andreas-Community-Response-300x249.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2012/04/Andreas-Community-Response.jpg 368w" sizes="auto, (max-width: 300px) 100vw, 300px" />
When I first joined 23andMe in 2009, Relative Finder was just being introduced and the Ancestry Finder feature did not yet exist. As I corresponded with my Relative Finder matches, I noticed that many of my potential relatives said that they were of Ashkenazi Jewish descent. I wondered if this high number of Jewish Relative Finder matches was typical for someone with Northern European ancestry, so I turned to the 23andMe community for help and posted my questions on the community forums. I communicated with fellow 23andMe users and quickly realized that my genetic profile wasn’t typical for someone without any Jewish background. Instead, my DNA confirmed the old family story and indicated that it was highly likely that I do have Jewish ancestry.
<img loading="lazy" decoding="async" class="alignright size-medium wp-image-12318" title="Andrea's GAunt and Uncle Ancestry Finder" src="https://blog-api.23andme.com/wp-content/uploads/2012/04/Andreas-GAunt-and-Uncle-Ancestry-Finder-300x164.jpg" alt="" width="300" height="164" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/04/Andreas-GAunt-and-Uncle-Ancestry-Finder-300x164.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2012/04/Andreas-GAunt-and-Uncle-Ancestry-Finder-271x149.jpg 271w, https://blogcms.23andme.com/wp-content/uploads/2012/04/Andreas-GAunt-and-Uncle-Ancestry-Finder-372x204.jpg 372w, https://blogcms.23andme.com/wp-content/uploads/2012/04/Andreas-GAunt-and-Uncle-Ancestry-Finder.jpg 469w" sizes="auto, (max-width: 300px) 100vw, 300px" />Here is my Ancestry Finder, with the settings focusing on the Ashkenazi Jewish segments. The blue spots are regions where a 23andMe customer shares a segment of DNA with me AND has stated that he or she has Jewish ancestors.
I decided to get my great-aunt &amp; great-uncle from that side of the family tested to see if they also had <a href="https://blog.23andme.com/articles/ashkenazi-ancestry-and-health">evidence of Ashkenazi Jewish</a> admixture. Around this time, Ancestry Finder, which has a specific section dedicated to Jewish ancestry, was introduced. This feature was also beneficial in my quest.
As I expected, my great-aunt &amp; great-uncle also showed significant Jewish ancestry — more than I have, because they are two generations closer to our Jewish ancestor than I am.
Thanks to DNA testing, we have clear evidence of a Jewish ancestor in our past for the first time. Without 23andMe, I might never have known if there was any truth to this family legend. Why did the Lewis family feel the need to convert from Judaism to Christianity and change their name? I am actively searching to uncover this information, but much of Nathaniel Lewis’s life story has likely been lost to history. However, his DNA lives on in his descendants and provides clues about his background. Often, when traditional genealogy methods fail, you can turn to DNA to uncover more about your ancestral heritage. You never know what sort of surprises can be uncovered!
<img loading="lazy" decoding="async" class="alignright size-thumbnail wp-image-12325" title="andrea 23andMe pic" src="https://blog-api.23andme.com/wp-content/uploads/2012/04/andrea-23andMe-pic-150x150.jpg" alt="" width="150" height="150" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/04/andrea-23andMe-pic-150x150.jpg 150w, https://blogcms.23andme.com/wp-content/uploads/2012/04/andrea-23andMe-pic-271x271.jpg 271w, https://blogcms.23andme.com/wp-content/uploads/2012/04/andrea-23andMe-pic-372x372.jpg 372w" sizes="auto, (max-width: 150px) 100vw, 150px" />
When she is not performing genetic comparisons on Family Inheritance Advanced or answering questions on the 23andMe community forums, Andrea Badger attends college at the University of Washington and will be receiving two bachelor’s degrees in June of this year. She writes the genetic genealogy blog at www.andreasancestors.com.

Finding a Family’s Jewish Ancestry

This month, 23andMe published a new article in PLoS One entitled “<a href="http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0034267">Cryptic Distant Relatives are Common in both Isolated and Cosmopolitan Samples</a>.&#8221; Authored by former 23andMe scientists, Brenna Henn and Lawrence Hon, along with current 23andMe scientists and 23andMe advisor, Itsik Pe’er, of Columbia University, the article describes the nuts and bolts of the method behind our innovative Relative Finder tool. In this post, Brenna discusses what the findings mean for our notion of “relatives” and explores the many special features of the 23andMe customer database.
By Brenna Henn
You probably know how many siblings you have or the number of first cousins. But do you know how many 2nd cousins you have? Does 38 sound reasonable? What about the number of 3rd, 4th, or 5th cousins?
The answer may surprise you.
<h6>What&#8217;s a Fourth Cousin?</h6>
Under a simple model where a family has 2-3 children, you would have 190 third cousins, 940 fourth cousins, and a whopping 4,700 fifth cousins.
Going back to 8th cousins (or 9 generations back to a common ancestor), the model we developed predicts you would have over half a million 8th cousins!
<iframe loading="lazy" src="https://www.youtube.com/embed/qG6BFjoXHvY" width="560" height="315" frameborder="0" allowfullscreen="allowfullscreen"></iframe>
Now, this model is a simplification because some families have a dozen children and some have none; but this model does help illustrate just how many potential distant cousins are out there.
<h6>Relative Finder Tool</h6>
Finding a relative in the 23andMe database, however, rests on two other important conditions. First, the relative has to be a 23andMe customer. Second, you and the relative need to share a long identical segment of DNA. The more distant a pair of cousins, the less identical DNA they share. Very small fragments of DNA can be hard to detect with our algorithm.
So although you might have thousands of 6th cousins, we think we can only detect about 4% of them with 23andMe’s current technology.
Our detection success is much higher for more closely related cousins, though — we can detect about 46% of 4th cousin pairs and 90% of 3rd cousin pairs.
<h6>Connections Among Those with Ashkenazi Ancestry</h6>
Our ability to detect a person’s distant cousins is also influenced by the ancestry of the individual. If you are Ashkenazi Jewish, you may have noticed that 23andMe’s Relative Finder feature shows you over a thousand cousins.
This is because Ashkenazi Jews are more closely related to each other than a random sample of European-Americans. Over the past several hundred years, a cultural tendency to choose marriage partners of the same ethnicity (also known as endogamy) means that Ashkenazi individuals are more likely to share the same ancestors.
In fact, we estimate that any two randomly chosen individuals who identify as Ashkenazi is on average the genomic equivalent of 4th-5th cousins because they share many recent common ancestors.
This phenomenon doesn’t just occur in the Ashkenazim.
<h6>Looking at Different Populations</h6>
We looked at 121 populations, many from the 23andMe customer database. Pairs of individuals in Iceland, Finland, or South Africa are more closely related than pairs of individuals from Italy or Japan.
<div style="float: right; text-align: left; width: 200px; padding: 10px; margin-left: 15px; border: 1px solid black;"><img loading="lazy" decoding="async" class="alignright size-full wp-image-12163" style="float: left; margin-right: 5px;" title="small_23andMe_logo" src="https://blog-api.23andme.com/wp-content/uploads/2012/04/JRBgdIBXKIeVIdETJrxYIw_ttam_logo.jpg" alt="" width="24" height="40" />Connect with 23andMe members who share DNA and ancestors. Not yet a 23andMe customer? <a href="https://www.23andme.com/store">Visit our store</a> or <a href="https://www.23andme.com">learn more</a>!</div>
In our analyses, we also looked at DNA data for over 5,000 individuals with just European ancestry in the 23andMe database. The DNA indicated that in this sample there are over 5,000 3rd cousin pairs and 30,000 4th cousin pairs. This result is important beyond thinking about genealogy.
It means that large disease association studies that sample thousands of individuals will have many pairs of distant cousins in the dataset. By identifying cryptic (or non-obvious) relatives in databases, researchers can see if certain disease mutations occur more often in different extended families.

Ashkenazi ancestry — Page 2