Using Genetic Matches to Understand Your Roots

Finding out the story of our ancestors, who they were and something of their personal history, involves a combination of genealogy research techniques, serendipity, and the science of genetics. Serendipity, the accidental discovery of something fortunate, is unplanned and cannot be anticipated. While it is always nice to have, serendipity cannot be your entire family history strategy.

This leaves us with family stories, census data and other sources of records for our ancestors. Sometimes these contradict one another. Should that happen, there are ways to evaluate and settle on the most likely answer. However, the final way to compare family history to current reality is DNA. Should DNA results contradict the family history, no matter how well researched, the DNA (as measured in a member of the family line being studied) is incontrovertible!

This is best understood by examples. I am going to use a fictitious Taylor ancestor and demonstrate what various DNA results will tell us. Let us begin with an imaginary ancestor, John Q. Taylor, born in 1824 in Belmont, Ohio, USA. As were all years, 1824 has its distinctions, on November 5th – Rensselaer Polytechnic Institute (the first technological university in the English-speaking world) was founded in Troy, New York, the Florida State capital moved to Tallahassee, where it remains, and Beethoven’s 9th Symphony premiered on May 7th. This ancestor (for our example we will assume he is our earliest known ancestor) grew up, married and produced four sons: Abe Taylor, Bryon Taylor, Charlie Taylor and Daniel Taylor. All four sons were born in Ohio in the period 1845-1860 and you have records of them and their marriages. Each produced at least one son who was named after him, Abe Taylor II, Byron Taylor II and so forth.

Skip ahead to the current day. You are Daniel Taylor IV born in 1950 in Louisville, Kentucky. (Or his close female kin.) You have records and a pedigree showing your descent from your great-great-grandfather, John Q. Taylor. You submit a sample and join the Taylor project.

Luckily, it turns out that there are existing samples in the Taylor project for three others of your third cousins, direct descendants of Abe Taylor, Byron Taylor and Charlie Taylor. Let us look at what the results might mean.

In our first case, let us assume each of these Taylor cousins does a 12 marker y-DNA test. In our example, all four match. Does this prove the family history? No! (Nor does it disprove the family history.) All a 12-marker match tells us is that these four men share a common ancestor sometime before 1200 AD, which predates the use of surnames. It does not tell us that they are third cousins, or that they are not.

What if you each tested 25 markers and had a perfect match? A perfect 25/25: The chances are 90% that your most recent common ancestor is within the past 28 generations, roughly since 1300 AD.

What if you tested 37 markers and had a perfect match? A perfect 37/37: The chances are 90% that your family lines are connected within 19 generations, most likely since 1530 AD.

If you find a perfect 67/67: The 90% probability level is a common ancestor no earlier than 1735 AD, with a 50% probability that your common ancestor is your great-great-grandfather.

These, however, are the easy cases.

What if, of the four descendants of John Q. Taylor in the Taylor project, yourself and three different third cousins, representing three different lines, three of you match 67-67 and one matches 65/67? While it is unlikely that there would be two random mutations in the same line over so few transmission events , it is within possibility that the four lines are connected as the paper trail indicates.

But let’s make this more complex. Three lines connect at 67/67, and the fourth line, which has an equally compelling paper trail, connects at 62/67. From mathematics, we know that the fourth line, with only a 62/67 connection, is not a recent cousin of the other three lines. Their genetic connection is before surnames came into common use in the English speaking world.

What can we conclude about these four lines? Most likely, three of the lines are the direct descendants of John Q. Taylor, and the fourth line is of similar ancestral stock, but not a direct descendant of John Q. However, there is also a possibility that the one individual is the sole true descendant, and the other three lines represent similar ancestral stock. And there is always a remote possibility that none of the samples is a direct descendant.

How do you proceed to understand more about these lines? There are several ways to proceed. One is to compare the 67 marker matches to all surnames at the Family Tree DNA project. If that line ends up having 15 perfect matches to individuals with the surname Miller, then there is a likelihood that somewhere between 1824 and 1950 either an adoption or a “non-paternal event” occurred that introduced the Miller genes into the Taylor family.

In addition to following the genetic science, you also want to further explore the family history. Was there a time that rumors spread about an affair? When husband and wife were separated? Follow that thread to find out more…

Lalia Wilson for the Taylor DNA Project

A Link to Dick Eastman's blog

Hi,

Here is a long article about family stories and how they many times are wrong. Read the comments, as well!

http://blog.eogn.com/eastmans_online_genealogy/2009/09/genealogy-myths-real-fools-gold-or-both.html

Lalia

67-Marker Matches

Hi Again,

I'm continuing with more material from Ralph Taylor on the meaning of matches. What does it mean if you match 67 out of 67, commonly written 67/67, with another person? There is about a 50% likelihood that you share the same great-grandfather! Thus, you are second cousins. You could be slightly closer related or slightly more distantly related, but you are related recently as genealogists measure relationship!

As Ralph Taylor says, "67-marker matches, if you’re lucky enough to find one, are very precise; you may need to account for the birth dates of the matching individuals. The main problem is that most people have done a lesser test, so you can only compare against the markers they had tested." Thus, refer to earlier blogs which discuss 37 marker matches and fewer matches.

Should you match in the range of 65-67/67: You share a common ancestor and he almost certainly lived within a genealogic time frame.

o A perfect 67/67: The 90% probability level is a TMRCA of <= 11 generations, >= 1735 AD; 70% is <= 6 gen., >= 1860 AD; & it’s 50% probable that your common ancestor is your great-great-grandfather.

o 66/67: 90% is <= 18 gen., >= 1560 AD; 70% is <= 18 gen., >= 1730 AD; 50% is <= 7 gen., 1835 AD.

o 65/67: 90% is <= 24 gen., >= 1410 AD; 70% is <= 16 gen., >= 1610; 50% is <= 12 gen., >= 1710 AD.

Should you match in the range of 62-64/67: You share a common ancestor, who may or may not have lived in a genealogic time frame.

o 64/67: 90% is <= 31 gen., >= 1235; 70% is <= 22 gen., >= 1460; 50% is <= 16 gen., 1610.

o 63/67: 90% is <= 37 gen., >= 1085 AD; 70% is <= 27 gen., >= 1330 AD; 50% is <= 21 gen., >= 1480 AD.

o 62/67: 90% is <= 43 gen., >= 930 AD; 70% is <= 32 gen., >= 1200 AD; 50% is <= 26 gen., >= 1360 AD.

We've have spent a number of blog entries discussing the statistical meaning of matches. You do not need to completely understand statistics or probability, though. What you do need to do is to investigate the family trees of anyone who closely matches you. For example, with a "perfect" match of 67/67, you and the other person should be able to find your common ancestor fairly easily. One hopes that each of you has some information about your mutual family tree so that you each gain significant new information. After all, that's why you chose to participate in this project.

The good news is that eventually sufficient y-DNA records and pedigrees will exist to satisfy every participant's desire for knowledge of their roots!

Best wishes as we move towards that goal.

Lalia

DNA and the Genealogical Time Frame

Hi,

We Taylor administrator team members have discussed moving this blog, and I was holding off on posting. But so far, it looks like the blog will remain here! This is a submission from one of the administrators, Ralph Taylor. Ralph has a keen interest in the statistical side to genetic DNA and he has submitted several other pieces which I'll post in the coming days.

Lalia
~~~~~~

Sometimes, Y-DNA matches point to a common ancestor who might have lived thousands of years in the past. Finding a name or other information about this man can be an almost insurmountable task; the range of time exceeds the"genealogical time frame".

While it's fun to imagine our Taylor ancestors fighting alongside King Arthur against the Saxons (or, fighting with the Saxons against Arthur) it's not genealogy unless we can link a line of descent with specific people. The International Society for Genetic Genealogy (ISOGG) defines "Genealogical Time Frame: A time frame within the last 500 up to 1000 years since the adoption of surnames and written family records..." Though extending to the present, the genealogical time frame (GTF) has no definite & universal beginning point. It depends on the practices and record availability of the specific area in which we want to look. But, we can make some general observations. Genealogy, linking individuals into a pedigree, depends on: 1. Surnames, to identify one John from another in the same place and time and suggest kinship; & 2. Written records naming most people in a community.

Surnames: If you've struggled with too many men of the same name in the same time and place, you know how important surnames are to genealogy. Without surnames, it gets even more confusing. The practice of surnames passing from father to children came into common use only as far back as the mid-14th century (about 650 years ago) in England and even more recently in other places. We believe it traces to a 1353 edict on the issue by King Edward III. With few exceptions, the occupationally-based Taylor surname dates from this time. Earlier ancestors would not have had a surname.

The Scandinavian patronymic system -- in which Carl, the son of Peter, was named Carl Peterson & Peter's grandson became Hans Carlson -- persisted into the 19th century. The Germanic practice of men "marrying the farm" and taking the farm's name lasted about as long.

Written records: In Europe, the practice of recording baptisms, marriages & funerals of parishioners began with the slow spread of the Christian Church. Written records were then adopted by secular authorities for other purposes such as taxes, military conscription and worker control. Written records are, of course, dependent on a written language and a minimum level of literacy. Many ancient languages had no written form, so monks & priests wrote in Latin. Even kings, whose first job was warrioring,were often illiterate.

The Bubonic Plague (also mid-14th century) indirectly stimulated record-keeping on previously-ignored ordinary folk. The plague killed two-thirds of Europe's population and the rigid feudal society as well. As serfs - whose masters had died - fled and masters - whose serfs had died -sought replacement workers, unprecedented movements of people & resulting paranoia were created. Suddenly, it was important to write down who was living in your town or county. Previous records (such as the Domesday Book of 1086) named only taxpayers, the aristocracy. Histories named only the major players -- the "stars", not the supporting casts. We are familiar the effects time has on written records. Courthouses burn, churches and archives are bombed, paper molders.

All these and more conspire to make records which once existed no longer available. The more time that has transpired since a record was created, the less likely it still exists.

Conclusion: I believe ISOGG is being generous with its "up to 1000 years", at least so far as Great Britain & Ireland (from which many Taylor families came) are concerned. I'd peg our GTF as beginning about 1350 AD. Genealogy isn't alchemy; we can't turn lead into gold. We can only work with what there is. Most of us have limits on the time, money and effort we can devote to family history; we have to set priorities. A DNA match pointing to a 90% probability of an ancestor who may have lived before 1350 may not be worth making a high research priority.

Welcome to the Taylor DNA Project Blog—Taylor Topics!

In the interests of serving project members and forwarding the educational and informational goals of the project; the project administers have decided to use a blog for communicating with members.

Our goal is to provide you with information that helps you understand your family tree and to connect with relatives and go further backward to previous generations in your family tree.

The blog will feature short pieces of information about DNA testing, Taylor genealogy, famous Taylors and associated topics.

If you have managed to have a breakthrough regarding your Taylor line through using this project, please send the story to Lalia Wilson (LaliaW@aol.com) so that we can share your story with other project members.

We look forward to hearing from you and answering your questions so that everyone’s questions are answered.