The Simple Way to Understand Genetic Genealogy Tests, Part 1

As a co-administrator of a y-DNA/surname project, I and my colleagues get many questions about what various genetic tests can do for people. The long answer probably requires an advanced degree in genetics… something most participants don’t have. Here is a simpler explanation which is true in the macro sense, though extended details are not covered.


Basically, there are three different kinds of genetic tests used in genealogy. One test is for markers on the y-chromosome. This test requires a sample from a male, as females do not have a y-chromosome. It looks at markers and allows you to compare them with other samples of known or unknown genealogies in hope that you will find a relative who proves a specific lineage.

The second type of test concerns mitochondrial DNA, the DNA which was in the egg from your mother (that became you!) and consequently the bodies of your cells today. Mitochondrial DNA comes only from your mother. It is only passed down a female line. Your mitochondrial DNA came from your mother and her mother and her mother back in time to the first human woman.


The third test is of autosomal DNA. Autosomal DNA is the DNA other than the sex chromosomes. In reproduction the autosomal DNA is mixed up with the creation of each new child, sometimes coyly referred to as a “transmission event.”

These three types of tests give us different information; and importantly, that information yields different genealogical information for different time periods.

Let us begin with our mothers and mitochondrial DNA. Mitochondrial DNA changes very slowly. One research paper recently reported a rate of one change per 371 “transmission events.” Thus, over 371 generations, there is a 50% chance that one child will have a change in her/his mitochondrial DNA. Population geneticists and genealogists define a generation as somewhere between 20 and 30 years. If we use 25 years here, we are talking about the likelihood of one change per 9,275 years. Now this change is random, so it could have occurred between you and your mother, but the likelihood of that is 1/371.

Here’s the simple way to look at this. Suppose we represent your mother’s mitochondrial DNA (mt-DNA) as a hand of four playing cards: the 2 ♦, the Queen ♥, the 10 ♠, and the Knight of ♣. The odds are that your mt-DNA is exactly the same (the 2 ♦, the Queen ♥, the 10 ♠, and the Knight of ♣); actually 370/371, or 99.73%. And if there is a change, it is minor and closely related. An example of a change would be represented by this configuration: the 2 ♦, the Queen ♥, the 9 ♠, and the Knight of ♣. We expect this same situation to hold true up and down your maternal line. A fifth cousin sharing the same maternal lineage will likely have the exact same mt-DNA with perhaps one minor change. For that reason, mt-DNA is very useful for establishing maternal shared ancestors, but of much less use to understand lineages in what we call genealogical time—the seven hundred years since surnames and some record keeping became more common. (Though royal lineages have been kept for thousands of years.)

Because mt-DNA changes so slowly, and because it is present in much larger quantities in people than other DNA and usually survives for years after death and burial, it is used to understand the genetics of earlier humans. One group of people killed by the Mount Vesuvius volcanic eruption of 24 August 79 AD (which destroyed the two ancient Roman cities of Pompeii and Herculaneum) was analyzed over 1,600 years later. The mt-DNA showed that six of 13 individuals in one house were maternally related, all having the unusual haplogroup T2b. Because of the slow rate of change of mt-DNA, scientists can confidently say that all of our mitochondrial lineages trace back to a common ancestor who lived in Africa 100,000 to 150,000 years ago. Some lineages migrated out of Africa about 60,000 years ago, while others remained.

I will return with further information about the rates of change for y-DNA and the autosomal DNA. The card game becomes much more complicated! Mitochondrial DNA changes so slowly you could think about dealing out the same four cards 371 times in a row. But for y-DNA (at 67 markers) it is just 3-4 hands in a row. And for autosomal DNA you get a new shuffle and a new hand with every transmission event.

Lalia Wilson for the Taylor surname project

The Case for Using Family Finder in a Surname Project

Members of the Taylor Project have almost all participated by means of y-DNA testing. You submitted a sample, provided a basic pedigree and the name of your earliest know Taylor ancestor and now (ideally) you are matched with a group of Taylors. Your group descends from a single line and the other group members are your cousins.

In an ideal world, you know your exact relationship with each member of your Taylor group. Knowing this relationship, each of you can now claim your combined paper trail of lineage.

Isn’t that why you have participated in DNA testing?

Well, it doesn’t always work out like that. And you, dear reader, may be one of the people who is an exception to the ideal portrayed above. This is where the Family Finder test can be of great benefit. The Family Finder test looks at autosomal DNA, which is inherited from all of your lines of descent, not just the male-to-male lineage of y-DNA or the female-to-female lineage of mitochondrial DNA. It is a way to investigate all your lines.

I’m writing this because there is a price reduction on this test for current FTDNA members. Take advantage of a major price reduction through June 22nd.

What can the Family Finder test contribute? Let’s look at several situations.

First, you are a male Taylor, you have a fairly close match with other Taylor project members, enough to form a group, but you don’t know your exact relationship. If you and others in your group do the Family Finder test (henceforth FF), you can close in on your relationship. For example, if your y-DNA suggests a 50% likelihood of a common ancestor within 6 generations, doing the FF will indicate if your common ancestor is within seven generations (the equivalent of 5th cousins) and suggest the number of generations between you. This should focus on exactly where to look for the paper trail indicating a common ancestor. It also may help identify a relative who has not yet tested who would be “the missing link.”

Second instance, you are a female Taylor. You don’t have any y-DNA, and you don’t know any living male Taylors of your line. Doing the FF test will allow you to match with Taylor males currently unknown to you. You can then use their Taylor group, from their y-DNA results, to work towards your earliest Taylor ancestor.

Third instance, you are a male Taylor. Your y-DNA did not match any Taylor line, but did match another surname project. The evidence is pretty conclusive that one of your male ancestors carried the name Taylor, but was not biologically a Taylor. However, you do not know when that NPE (non-parental event) occurred. Was it in your generation? Five generations? More? With the FF test, you can compare your results with other known Taylor relatives, second cousins, great aunts and uncles. If you match them, the likelihood is that the NPE occurred prior to the births of all those tested, and that a common ancestor of all of yours came subsequent to the NPE. (However this inference cannot extend beyond seven generations due to limitations of the testing, nor can it extend beyond the parameters of your individuals sampled.)

Fourth instance, you are a male with a non-Taylor surname. Your y-DNA matched the Taylor line in multiple close matches. You don’t know when the NPE occurred. You do the FF test. If you match a Taylor group with the FF in addition to y-DNA, this suggests the NPE occurred within the last seven generations. It may be fewer generations depending upon the FF results. At least you can begin to discover your roots.

Finally, what about the unique individual who has tested 67 y-DNA markers and mt-DNA and has no matches? I know one of these people. We hope with the FF test to finally find someone who matches!

I look forward to us all finding out our ancestry.

Lalia

Beginning Steps to using Family Finder or Autosomal DNA Tests

We are getting queries and getting results with the new Family Finder test available from Family Tree DNA.  There are many benefits to using Family Finder.  One is to confirm how collatoral branches of families link together.  This will become quite useful to the Taylor project over time.  Even today we have "matches" where we can confirm that two or more individuals with different pedigrees have "related" DNA, but we do not know from the y-DNA or the paper trail exactly where the lines converge into a common ancestor.


With Family Finder we should be able to see where two (or more) lines converge if it is within the last seven generations.  This is because Family Finder works best with relationships at the 5th cousin or closer range. 


One of the steps in using Family Finder, other than submitting a sample, is to provide a list of surnames in your family line.  I have done this for my direct line and will include it below as an example.  Since the test goes out to fifth cousins, ideally you will go out to your seventh generation in lineage.  I have a couple of gaps, but most of my other 5 times great-grandparents are included.  Some of the surnames are duplicated, so that reduces the number and for some I give alternate spellings.

• 
  
  Augustus
• 
  
  Barteaux/Berteaux
• 
  
  Beall/Bell
• 
  
  Born
• 
  
  Bright/Brecht
• 
  
  Cassell
• 
  
  Crockwell
• 
  
  Dickerson
• 
  
  Foster
• 
  
  Gaston
• 
  
  Glover
• 
  
  Harbaugh
• 
  
  Hinton
• 
  
  Hockersmith
• 
  
  Hutt
• 
  
  Jackson
• 
  
  Johnson
• 
  
  LeCain
• 
  
  Leonard
• 
  
  Lingenfelter
• 
  
  Lockwood
• 
  
  Madden
• 
  
  McDonald
• 
  
  Mead(e)
• 
  
  Moore
• 
  
  Perry
• 
  
  Pope
• 
  
  Pulliam
• 
  
  Rice
• 
  
  Ritchie
• 
  
  Robinson
• 
  
  Ryerson
• 
  
  Scott
• 
  
  Simon
• 
  
  Smith
• 
  
  Spence
• 
  
  Springer
• 
  
  Starratt
• 
  
  Stone
• 
  
  Taylor
• 
  
  Vail
• 
  
  Wheat
• 
  
  Whitman

 Assembling that list of surnames will be vital to matching records--documented paper records--when you get a Family Finder match.  It's time to start your own list!

Lalia Wilson for the Taylor Surname Project

Some new information about predicting appearance from DNA

Hi,

As fans of genetic genealogy, we are always interested in new applications.  Here are a couple of articles about predicting appearance from a DNA sample:

http://io9.com/5542776/how-forensics-experts-use-dna-to-create-mugshots-of-a-criminals-face

http://www.scientificamerican.com/article.cfm?id=portrait-in-dna

Both of these articles feature a recent study that identified characteristics of a man who lived over 4,000 years ago.  His blood type was A+, he had indicators for male-pattern baldness, dark skin, and was likely stout or square of build.

It may be that within years there will be genealogical applications for this.  Could the future bring a DNA test that allows us to "see" some of our ancestors?

Lalia Wilson for the Taylor DNA Project

A Model Letter to Promote the Taylor Project

Hi Fellow Taylors!



Whenever I run into a new Taylor in my life, I tell them about the Taylor project. It's hard to explain in a simple soundbite, and sometimes I'm less than successful. So I met yet another Taylor Tuesday evening, and got his e-mail and sent him this letter. It is adapted from the letter we are now sending to anyone who contacts the project, without yet being a member. I recommend you take it and modify it to your needs. I'm wondering, myself, if it would be too OCD to carry copies in my purse to hand out...



See letter below.



Lalia

~~~~~~~~~

Dear...



Here is information about the Taylor DNA project, hosted by FTDNA (Family Tree DNA). It allows you and the rest of us find our ancestral lines. Our Taylor Family Genes project posts the DNA results and family trees for members of the project. The public is welcome to view our public page, http://freepages.misc.rootsweb.ancestry.com/~taylorydna, and to explore the FTDNA websites--which together have a wealth of information about genetic genealogy and about the Taylor project.



To become a member, you'll need to go to FTDNA, http://www.ftdna.com/, and click on the "Products" tab at the top of the page and scroll down to the list of tests, then order a kit. There are many products available so we recommend our new members purchase the 37 DNA marker test (or the 67) because when you do get a match, it is easier to zoom in on the generation in which a common ancestor lived. These kits are for men. For Taylor women with no male Taylor to be tested, you have the option of following your maternal line, through testing mtDNA, or testing autosomal DNA, through the new Family Finder test. These two tests are also available to males.



Once your kit is turned in for processing there's about a 1 month waiting period for your results to come back. You can join the Taylor surname project at that time and we will request that you send your family tree to be posted on the site. Once your markers are in, FTDNA will post them and send you a certificate with all the data.



We hope this has given you the information to get you started. We look forward to you joining the 350 Taylors already participating in the project, who currently are sorted into about 35 family groups (i.e. related markers) and a number of "singles" awaiting family matches.

Newly Available Technique at FTDNA

Greetings,

Family Tree DNA has announced to current members that they can do autosomal testing of their DNA. This new test is called Family Finder by FTDNA. So here's a quick explanation of what that means. If you are a member of a surname project, such as the Taylor project, you have had y-DNA tested. This is the Y-Chromosome which is inherited from father to son throughout history. The minor changes that occur in that chromosome happen such that over generations family lines separate. Y-DNA is extremely useful to determine one's patrilineal lineage.

Similarly mt-DNA is testing the genetic material that comes only from one's mother. She got it from her mother and so on back in history. Mitochondrial DNA mutates more slowly than y-DNA, making it less useful in following one's ancestors in historical time, but more useful, perhaps, for deep ancestral investigation.

Autosomal DNA is the DNA in the 22 chromosomes that do not include the final 23rd chromosome that determines whether we are male or female. Thus the remaining 22 chromosomes have genetic pieces from all our ancestors, not limited to our father's direct paternal line or our mother's direct maternal line.

Family Tree DNA proposes to test your sample, should you request the test, and compare it with their database of samples. They assert that with this test you can locate genetic relatives in the database from as far removed as 5th cousins. This would include relatives unknown to you, who may have been lost to your version of your combined family history. While the new autosomal testing will be administered separately from the surname project to which you belong, it will provide useful information that may enhance your knowledge of your family tree. See the quote below from the FTDNA website:

"Surname projects can use Family Finder to better define branches in a family tree. By using Family Finder testing, close Y-chromosome and mt-DNA matches without traditional records may be assigned to a pedigree with greater confidence. Even more exciting, surname projects may now bring female cousins into the project as additional evidence."

Lalia Wilson for the Taylor Surname Project