Understanding DNA Testing


Why should I get tested?
You should get tested if it will aid in defining the DNA profile of your surname ancestors. When your DNA profile is combined with another descendant of a common ancestor, it can define the DNA profile of that earlier ancestor. When combined with your brother’s result, your test will define the common ancestor (your father). When combined with a 5th cousin’s DNA, your result will define the result of your gggg-grandfather.
For a man who has already had a close relative tested, there may be little value in his additional testing unless there are specific questions to be answered.
Of particular concern are the sole surviving male representatives of a family line. Once they are gone, their family cannot be directly represented. These men are particularly important to their family study and should be strongly considered for testing. Many families already have stories of DNA testing a family member who has since died, or of not getting a test on a family member before they passed on.
How useful will DNA testing be for me?
The answer will vary for each individual. For a man with a distinctive DNA profile who matches into a family whose profile has already been established, the result can be quite useful, as it can confirm his family and leave only the question of which members are his actual direct ancestors. For the man whose result matches multiple distinct families of the same surname, the result can be ambiguous. For the man who fails to match any other participant, the result can be quite frustrating. Over time, as additional markers and participants are added, we can hope that results for the latter two become as useful as they are for the first case.
Once I've decided to be tested, how do I choose a test?
You have a choice of two basic tests in the genetic genealogy field: yDNA for the male (paternal) line and mtDNA for the female (maternal line).
  • Only males can take the yDNA (surname) test, which traces their father's father's ... father's paternal line.
  • Both males and females can take the mtDNA test, which traces their mother's mother's ... mother's maternal line.
  • You can also order a combination test for a man, which analyzes his yDNA and mtDNA.
Persons testing yDNA for Surname research at Family Tree DNA (FTDNA) should test through a project, as the cost is $50 to $80 less than testing as an individual.
Here are the simple rules:
  • a man you are testing with yDNA must be directly descended from the (male) ancestor you are interested in researching - with no females between them (yDNA cannot pass through a female ancestor)
  • a person testing with mtDNA must be directly descended from the (female) ancestor you are interested in researching - with no males between the test taker and ancestor being researched (mtDNA cannot pass through a male ancestor)

How much does it cost?
Testing cost varies. If you know the surname you should match, you can probably get by with 25 markers. We have noticed that most folks who are serious about their genealogy will end up with at least 37 markers and possibly 67. If you are trying to match to a different surname without a paper trail – you will need at least 37 markers and will likely benefit from 67. One approach is to start with as many markers as you can comfortably afford and then upgrade later, as the need arises. You also have the possibility of going in steps, upgrading a bit at a time. Prices:
12 markers $99
25 markers $148
37 markers $189
67 markers $269

Upgrades from one test to the next are $49. (37 to 67 is a two step increase and is $99)
Where should I go to get tested?
The best way to be tested is as part of a Surname DNA Project. As there are some differences in the markers tested by the various testing companies, it is quite helpful to obtain a test from the same testing company as other men with your surname. When a Surname Project has not already been started, consideration should be given to starting one.

ow do you protect my privacy?

Our approach is to separate the person providing the dna testing from the reported information. We give that person a number. Only the person ordering the kit, the project administrators, and the FTDNA staff know his identity. Or, you can completely hide the test representative's name or address - by using a dummy name and by sending the kit to the sponsor's home.
We report the dna results and tie them to the earliest known ancestor, the family pedigree (which stops around 1900), and the researcher associated with the test. It is up to the reseacher to divulge more info.
We will blind copy or forward a request for contact, but won't give out contact info.
The individual has the ability to allow comparisons only within the project. To completely conceal your identity, one approach is to list only the earliest known ancestor.
FTDNA has a good section on Privacy

When should I expect my results back?
Allow 6 to 8 weeks from the time you return your kit.  You can track the progress of your test through the labs by going to your personal page at FTDNA and clicking on "Pending Results".  To learn more about using your personal page, click here.

What will my results look like?
The appearance varies by testing company, but the critical information typically comes in a simple table. The result is primarily a listing of the markers that have been tested, plus a number for each marker.  To see the results for the Bentley Project, click here

How do I interpret my results?
Generally, you interpret your results by comparing them with the results of other participants. (See Understand Your Results.)

How do I compare my results to other people?
Results are compared by tabulating the number of “matches” you have with one other participant. A comparison for a low-resolution test might give a result of 8/12, 11/12 or 12/12, while higher resolution tests might give a 23/25, a 25/26 or a 34/37 result. (If you have a 37 marker test and are comparing with someone who had a 12 marker test, the best result that you can have with them is 12/12)
I'm female. Can I be tested?
Yes. Mitochondrial DNA (mtDNA) looks at the DNA that both women and men inherit from their mother's side. A mother passes her mtDNA to her children, but only females can pass it on. This represents the mother’s mother’s…mother’s maternal line. Your mtDNA result can be compared with another person’s mtDNA to see if you share a common female ancestor. Anyone can take this test. 
Mitochondrial DNA (mtDNA) tests the deep maternal ancestry (think 1000s of years) As mtDNA mutates very slowly, it becomes a link to your distant past - giving you the mtDNA of your mother's mother's ... mother's line. By testing, you learn your haplogroup– which tells you which "branch of woman" you descend from on your maternal side. In addition to learning your Haplogroup, you'll be told of the mutations that are present. These allow you the possibility of locating those with whom you share a maternal heritage. Often, this is too far in the past to be able to link paper trails, but a number of folks have started mtDNA projects to increase the learning. We have a lot of hope for the potential. Learn more about mtDNA.. Additionally, you can sponsor a male from your surname family of interest. This allows you to participate in your ancestral surname DNA project. Surname DNA (yDNA) looks at the DNA that a man inherits from his father's (paternal) side. This represents his father’s father’s … father’s line. The y-chromosome (yDNA) results are compared with two or more men to see if they share a common male ancestor. You will need to find a male who shares a common male ancestor with your female ancestor to be y-DNA tested. This male must be directly descended, through males, from your common ancestor. Sometimes you'll have to go back up the family tree and come back down to a living male that shares a x-grandfather with you and carries the surname you want tested.
For example: Did your great grandmother have brothers? Did they have sons? Did their sons have sons?
Did your great-grandmother father have brothers? Did they have sons? Did their sons have sons?
Any one of the men you find with the above questions can represent your family with a yDNA (surname) test.
Here's a link to an inheritance chart at Family Tree DNA that may help explain more clearly:

Can this test determine paternity?
In some cases, these DNA tests can be used to determine paternity and or questions about siblingship, however, the FTDNA lab is not AABB certified. If the participant needs something that will hold up in court or as proof for any legal purpose, these FTDNA tests will not be appropriate. If you only wanted to know out of curiosity, then it would be fine. Here are some examples given by Thomas, who runs the FTDNA lab in Houston.
Case 1: Two brothers
This can be (partially) solved by a Y-STR analysis. If you can exclude a paternity from another man in the direct male line, this is usually proof enough to confirm paternity. If it is a mismatch this is definitely an exclusion of a common paternity. No sample from the mother is needed.

Case 2: Two sisters:
This case can be solved very nicely with X-STR testing. The two sisters need to match at one allele of their allele pairs at all markers, because the father has only one X chromosome that needs to be inherited to both daughters. A sample from the mother isn't needed, but it could improve the confidence.

Case 3: A brother and a sister.
This is the worst case to resolve. Only autosomal testing is possible because the siblings have different sex chromosomes from their father's side. Without a sample from the mother I would never recommend to try to test DNA because the result will not tell anything useful. Usually the likelihood of a shared paternity (versus unrelated) is smaller than 90% which means in (at least) 10% of the cases you receive the wrong conclusion from the lab. So to really get a satisfactory result you should check Case 4.

Case 4: Three or more siblings of any gender.
With two confirmed siblings you may be able to reconstruct a partial autosomal profile from the father's missing DNA. Then you can compare this reconstructed profile with the third sibling. A sample from the mother is strongly recommended, because it will dramatically increase resolution. To be able to reconstruct enough unique allele combinations"

Right now, these tests are only available to existing FTDNA customers, but they hope to expand that in the near future.

Are there any downsides to getting tested?
A possible downside is that one may not get the result that one hopes for, or expects. For many people, that will be viewed as additional information and they will continue their research. However, for those individuals where that result causes significant distress, it could be a downside.

What if I get back results I don't like, such as indications of a non-paternity event?
Non-paternity results did occur and they may be obvious through DNA testing when the result is being compared in a well-documented family.
There are several scenarios that fit into the category of non-paternity event.

    • One, of course, is infidelity, but this may not be the most common
    • Another common event was the unrecorded adoption. As there were many adult deaths on the frontier, children were frequently raised by relatives or friends, with the adoptive parents giving the child their own last name.
    • Another occurrence that fits into this category is the unrecorded name change - which causes the same confusion
    • Where infidelities or adoptions have long been rumored and now proven, there can be some satisfaction. Where an infidelity or adoption occurred in a well-documented family, identifying it helps in clarifying the DNA profile of descendants. Where the non-paternity event occurs in a family without extensive documentation, it can be very disruptive and prevent the participant from obtaining matches within the surname.

Will this test tell me about medical conditions?
No. (The DNA evaluated in this test is often called “junk DNA’ because of its lack of medical information.)

 Will it tell me if I'm illegitimate?
Not unless your father is also tested. (There are other DNA tests that consider different markers that are more useful for legitimacy testing.)

Who has access to my results?
Testing Companies and Surname Projects historically allow the test participant control of access to their identity and disclosure of their results. Confidentiality is paramount in all testing companies listed here. You can share your data publicly on databases by encoding your results with a kit number and an ancestor’s name. This is sufficient for others, who have a genealogical interest to find and to contact you. In this manner, you can share your test data without revealing your identity or the identity of the testee, if it is from some one other than yourself.
Typically, the results are identified by a code. Only you, the Surname Project Coordinator and a small number of employees of the testing company can correlate your identity to your code number.
Most Surname Projects list the results of all participants together in a table, with most only identifying the participant by his code number and/or by the earliest known ancestor. A number of projects allow the participant to self disclose his identity.

Can insurance companies use my findings against me?
There is nothing in your DNA result that is of interest to an insurance company. Y-DNA testing is extraordinarily specific to just the markers of interest to genealogists. These markers exist in so-called “non-coding” regions of the Y-chromosome. (The DNA evaluated in this test is often called “junk DNA” because of its lack of medical information.) The Y-chromosome contains very little genetic data, and those regions of the Y-chromosome are not tested in any case.

What about police investigations?
You are not uniquely identified by this DNA testing. Your result cannot be correlated to DNA samples used in police work.

Will the testing company sell my results to anyone else?
No. Each testing company makes a written commitment to you respecting your privacy. You have to sign a release to even get your results compared to other participants in their database.

Will I find out I'm a different race?
I am not sure whether this is a hope, a fear, or a curiosity. Once in a great while, we have a white American who is absolutely sure of his paternal heritage who has an African result. As the Roman soldiers were from all over their Empire, including Africa, it is easy to imagine an African-born soldier settling in Northern Europe nearly 2000 years ago, taking a local wife and having a son, who had a son, ... and so on. After so many generations, that man looks as Northern European as anyone can,. but still carries the yDNA of that ancient ancestor.

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