Accidental Adventures in Genetic Genealogy: How DNA Can Break Down Brick Walls

A Genealogist Like You

Ever since I was bit by the family history bug over 15 years ago, I have remained an avid genealogist. However, I must admit that after years of relentlessly picking the brains of the living, scouring the records of the dead, surfing the net, traveling to genealogical meccas like Salt Lake City and corresponding with foreign archives, I eventually found myself nearing the end of the research road, or so I thought!

One day I inadvertently plunged into the gene pool and started cavorting with chromosomes. Next thing I knew, I had re-invented myself as a DNA detective and was making discoveries that stretched my family history back centuries, even millennia. On one line I discovered ancestry going back to the time of Moses. On another line I proved the connection between two huge family branches for which no record of a connection existed. On a third line I was able to deduce their pattern of migration since the late 13th century. On two of my lines I discovered evidence that some distant relatives had changed religions and moved to different countries. The list of findings goes on and on, but the best part has been that my DNA research has put me in contact with dozens of fascinating new cousins who’ve reignited my genealogical fire and enriched my sense of family.

What follows are just a few examples of how DNA made all these discoveries possible. But first here is a nutshell summary of the science behind using DNA for genealogical analysis.

A basic fact is that all genetic material changes (mutates) over time. However, the genes on our sex-linked chromosomes (Y for men, mitochondria for men and women) mutate much more slowly than the others and the average rate of that mutation is known. So when geneticists compare the Y or mitochondria DNA of different people they can tell, based on how closely specific genetic markers match, whether individuals are related and, if so, approximately how long ago their common ancestor lived. Also, groups of people who all originated from one geographical area typically have distinctive genetic patterns. (For more details on the math and science involved, see the references at the end of the article.)

The Adventure Begins: Case Number One

I first delved into DNA analysis because of a quirk of my Jewish ancestry, although as you will see, most of what can be learned through genetics applies to anyone, regardless of their heritage. Nevertheless, my interest was first piqued when I found out that genetic analysis was available to the public and you could use it to see if you had the genetic markers proving Jewish priestly descent.

Let me explain this a bit.

I had learned that my surname “Katz” was a shortened version of “Kahan Tzedek,” which in Hebrew means “righteous priest.” I further learned that this surname was taken by Jewish families who believed they were descended from the ancient priests, i.e. the sons of Moses’ brother Aaron.

My Katz family had not been religious for many generations and I’d never been told of our “priestly tradition.” But when I visited the graves of my great-grandfather and great-uncles, I discovered that the stones all had a symbol of two palms with fingers outstretched, which was used by Jews who believed they descended from those original priests.

So I was intrigued when I heard that a genetic study of Jews worldwide had found most Jews who claimed priestly descent — known by the Hebrew term cohanim — had a matching set of markers on their Y-chromosome DNA. What’s more, these markers indicated that those Jews had a common ancestor living about 3300 years ago. How cool was that? The tradition of cohanim ancestry, handed down in Jewish families for hundreds of generations, had a basis in genetic fact! When I learned anyone could have this analysis done for his or her own family, of course I had to try it.

Well, I next discovered that not anyone could do the test. Because the markers being looked at were on the Y (male) chromosome, the DNA sample had to come from a man whose paternal line was the one being researched. So I called my dad who readily agreed to swab his cheek for the family cause. Three weeks later I got the news that my dad’s DNA did indeed have the genetic markers showing cohanim descent. In one fell swoop, I’d pushed my Katz family line back to 1300 B.C.E!

As exciting as this result was, I expected it to be the end of my foray into genetic testing, but as things turned out it was just the beginning.

Daddy’s DNA Keeps Talking: Case Number Two

As time passed, and laboratory analysis became more sophisticated, I was able to have my dad’s DNA sample evaluated for additional information.

For example, I had analysis done on his mitochondrial DNA and learned his maternal line came from ancestors who settled in the Near East about 75,000 years ago and stayed there even though most of the people around them migrated north into Europe. From a “deep ancestry” DNA analysis, I learned that my Dad’s ancestors belonged to a population group that by about 40,000 years ago was 84% European and 16% East Asian. A surprising mix! All these results came with graphs and charts to help explain what everything meant. Although DNA analysis couldn’t tell me exact names or dates, it was a thrill to look through this DNA window and see the ancient beginnings of my family story.  However, the best was yet to come!

Another by-product of having my dad’s DNA analyzed was that I was put in contact with other people with whom my dad’s DNA was a genetic match. When my dad’s results matched with someone else, depending on the number of markers analyzed and the precision of our match, we got estimates of the range of years in which our common ancestor lived. In the case of my dad’s Y-DNA, within a year or so I’d been matched up with eight different families, located across the U.S. and even in Argentina. The exact numbers varied with each matched family, but overall we had a great likelihood of a common ancestor who lived between 100-300 years ago. As we started comparing our genealogical knowledge, I put together a whole new picture of where my Dad’s family must have come from before they settled in the Ukraine, which is where I had previously traced them to. I also discovered fascinating details on where other branches of that family must have migrated!

Questions I’d Never Dreamed to Ask: Case Number Three

I hit a brick wall very quickly on one of my mother’s family lines, so for years I just ignored it. Then one year I serendipitously hooked up with several genealogical fanatics who as it turned out descended from that same family line. By pooling our information and talents, we quickly assembled a phenomenal, drama-filled family history that stretched around the world and reached back six generations to a single patriarch. However, a huge mystery remained. There was one family group who shared our surname and many of our stories, but we couldn’t find a link to a common ancestor. I suddenly thought, “Could genetics solve the mystery?”

After a flurry of emails and a search for male cousins who were descendants of our family patriarch, we arranged for someone from my branch of the family and someone from the “mystery” group to send in DNA samples for analysis. Imagine our disappointment when we learned the two samples didn’t match! We weren’t related after all, at least not on the paternal side. Ironically, we later found evidence that the mystery branch's patriarch was adopted into the family and this explains why the male ancestry DNA showed no connection. We'd never have considered the adoption angle if we hadn't been pushed to do so by the DNA results!

So I had the answer to the question I’d originally asked, but then it turned out the DNA had much more news for me!

I hadn’t gone into the testing process to find random matches, but in a very short time, twelve families — all previously unknown to each other and all bearing different surnames — were identified by the lab as matches to my family. And most of those matching families were being researched by genealogists who had traced names and locations back for many generations. Given that we all now knew we had a common ancestor and since our degree of genetic matching indicated approximately when our different families “branched off” from each other, we swapped family history details and gained a wealth of information on the likely geographic locations of our earlier generations. All twelve families were Jewish, and although I had only been able to trace my family back to 19th century Lithuania, I was now able to deduce that my family’s 18th century origins were likely in Belarus and their 17th century origins were likely in Prussia.

Then the big shocker hit.

We were notified of a new match with a Protestant gentleman who’d researched his Protestant paternal line back into 17th century Maryland and knew that before that his ancestors had lived in England.

What? How could this man’s family possibly be a match with the rest of us? To help figure it out, several of us, including our newest match-mate, had more markers on our DNA samples analyzed to give us more specific results about when our common ancestor lived. We found out that the ancestor common to all of us, including the new match, had lived much earlier than the ancestor common to the “Jews” only. Indeed the common patriarch for all thirteen matching families most likely lived sometime around the 14th century.

You have probably discovered that world history can often shed light on your family history. In our case, the key historical knowledge was that Jews were expelled from England at the turn of the 13th century and only those who converted were allowed to return. Those who did not convert settled mostly in France and then, as the centuries passed, many continued on an eastward migration across Germany, into Prussia, Poland, and what is now Belarus. Armed with those facts, we could now speculate on a likely scenario to explain our genetic matching: One of our patriarch’s descendants must have become a Christian convert and returned to England, with his descendants eventually losing awareness of their Jewish origins. The patriarch’s descendants followed the typical historical migration path of Jews through Europe. Thanks to the DNA evidence, although we might never be able to get specific names and dates, we could feel fairly certain of where our ancestors had been over the last 800 years. Awesome!

A Tale of Two Families: Case Number Four

One day last year it dawned on me that a DNA analysis could quickly either prove or deny a major family connection I was researching.

The family lore was that two brothers who had come to the U.S. in the 1890s had fallen out and gone their separate ways. One brother had kept the surname spelled the original way; the other brother changed the spelling. One brother was my great-grandfather, and I had a lot of details on his descendants. I’d also contacted some descendants of a possibly-related family whose surname was spelled differently. While there was circumstantial and anecdotal evidence, I couldn’t find proof that the patriarchs of the two families I was researching were indeed related. Had I been wasting my time?

Once I decided to do this DNA analysis, I faced an immediate challenge. The family I was researching was on my mother’s paternal side, but since I needed Y-DNA my mother couldn’t give the sample. Her brother, mistakenly believing that personal medical information would be revealed if he gave a DNA sample, refused to help out. Luckily one of my mother’s 80 year old first cousins was up for the job. Then I turned to an 80-year-old contact in the possibly-related family branch who was ready to settle the issue once and for all.

A few weeks later, we got the news that these two octogenarians were a perfect match on all their markers! That meant that they had a common ancestor within the last one to three generations. I already knew for a fact that their common ancestor wasn’t their fathers or their grandfathers, so that meant their common ancestor had to be their great-grandfather. And this meant their grandfathers were brothers. Voila! I had my proof of the “two brothers” tale and inherited a huge new branch for my family!

Concluding Comments

The process of having a DNA sample analyzed is fairly straightforward. Different labs offer different combinations and deals, but the results they give are compatible and can be compared to results from other labs. (The one exception is the test for cohanim ancestry, which I believe is currently only performed by Family Tree DNA — see below) A test kit can be ordered and paid for online and mailed to you. (You can order a kit for yourself, or for someone else.) One collects a DNA sample by brushing the inside of the cheek with cotton swab(s) provided in the kit and then returning the swab in a pre-addressed postage-paid envelope.

You may wonder about the expense of all this DNA delving. Depending on what kind of analysis is done, to what level of precision, and with what lab, the costs for evaluating your DNA sample can run from around $100 to $500, although under $200 is most typical. While these amounts are not to be sneezed at, those who’ve spent hundreds or even thousands of dollars over the years on ordering documents, traveling to archives, etc., will find the bang for these bucks is pretty big. Also, a group of extended family members will often be willing to split the cost of having one person’s DNA analyzed, since that DNA sample will speak for all them!

The field of genetic genealogy is constantly being expanded and refined, so the best is yet to come. I encourage you to explore what you can learn about your own family history with this fascinating new research tool.

Debra Katz Klein, in addition to her genealogical pursuits, works as a preschool teacher and is developing family history based storybooks for young readers. She lives with her husband and two pre-teen children in Los Altos, California.

by Debra S. Katz

© 2011 The New York Genealogical and Biographical Society

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