The story by Elie Dolgin - "Newer DNA Tests Uncover Hidden Jewish Bloodlines" - discusses both 23andMe and FamilyTreeDNA.
It covers University of Chicago genetics doctoral student Joseph Pickrell's DNA odyssey along which revealed similar results to an Ashkenazi Jew, New York attorney Dan Vorhaus. Pickrell was raised Catholic but his results led him to ask his mother about the results.
She did some sleuthing among other relatives, revealing that:
"her father’s father — Pickrell’s maternal great-grandfather — had been raised Jewish in Poland before moving to the United States, where he married a Catholic woman and left his Jewish upbringing behind.The story also mentioned FamilyTreeDNA.com's tests to uncover Jewish origins. Many Hispanic Americans descended from Jews forced to convert or hide their religion more than 500 years ago in Iberia.
“It’s amusing that using genetics, I could wrestle this out of the bushes,” Pickrell said.
The story does explain 23andMe's test and why it produces those results.
A molecular anthropologist in Estonia, Richard Villems, is quoted as cautioning against jumping to conclusions based solely on DNA unless there is corroborating evidence, like Pickrell's ancestor.
Another section goes further, answering in part the question about what happens once a person discovers such a link.
Pickrell said he has no plans to start going to synagogue. And since “genes do not define the Jews,” according to Edward Reichman, an Orthodox rabbi and physician at Yeshiva University in New York, the Jewish community at large probably won’t embrace him, either. But according to Bennett Greenspan, president and CEO of Family Tree DNA, many people who learn of Semitic ancestry through DNA often end up converting to Judaism.The comments, as always on this type of article, are always interesting and cover the spectrum of belief. One, by "Jack," reads:
Elliot Dorff, a conservative rabbi and ethicist at American Jewish University in Los Angeles, welcomes these conversions. “We would really want to encourage such people to rediscover their Jewish roots,” he said. Although people who find Jewish origins through DNA are not strictly Jewish, halachically speaking, Dorff noted that many people in this situation already feel a deep-seated connection to the religion.
Read the complete story and all the comments at the link above.Bennett Greenspan regularly presents the services of Family Tree DNA at Crypto-Jewish studies symposia. Also in attendance at these events are Hispanic Americans interested in the potential Jewish ancestry of their families. It would not be an overstatement that a Levantine genetic signal only confirms the Jewish background that many of the test subjects either already suspected or were convinced of. The DNA test is merely a confirmation, not a revelation, afterwards conversion to Judaism is a small step.
Tracing the Tribe always recommends that those with known or suspected Jewish roots test with FamilyTreeDNA because it has the largest DNA database, which also includes the largest Jewish DNA database. Nearly all Jewish genealogists test with the company because of the large number of samples, which increases the probability of genetic matches.
There's a related 2010 Forward story covers how Rabbis and Halacha Grapple With Advances in DNA Technology:
Read that complete story at the story link above.Advances in genetic analysis and its medical applications are bringing unprecedented, if uneven, change to the world of Jewish law. Most often, the matter of genetics is considered in the context of issues on either end of life’s spectrum: those that relate to fertility and to the identification of post-mortem human remains.“DNA analysis is gradually meandering its way through the halachic literature,” said Dr. Edward Reichman, an Orthodox rabbi and associate professor of emergency medicine at Albert Einstein College of Medicine, where he is also an associate professor of bioethics and education.“Science has opened up a huge area of research and treatment in the area of the genetic code that just didn’t exist 25 years ago. All of those developments have required authorities in Jewish law to consider what effect it has on their approach,” said Rabbi Avram Reisner, spiritual leader of Baltimore’s Congregation Chevrei Tzedek and a bioethicist who sits on the Conservative movement’s Committee on Jewish Law and Standards.