In bringing this service to our family, the principal goal of the Terriot Acadian Family Society is first and foremost to help those family members who for any number of reasons, wish to confirm their relationship to the Terriot family. Secondly, the Society will use the results to study specific genealogical questions that have not been resolved to date and that will enhance our genealogy. Some examples are given below.

This web page was created by Karen Theriot Reader, administrator of the Terriot Surname DNA Project for the Terriot Acadian Family Society. Karen is also a researcher and genealogist for the Theriot family in Louisiana. She is the delegate with the Terriot Acadian Family for the Joseph Elric Theriot and (Bessie) Leora Margaret Cahill Great-Branch [MRIN 1167] of Santa Ana, Orange, California, USA. Her short-biography is available here.

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Genetic genealogy is an exciting new tool for family genealogists and historians. There are two entirely different DNA tests currently available for genealogists. Through testing of the Y chromosome, any male can validate a descendancy from a particular surname, and can even broadly estimate the time to the  Most Recent Common Ancestor (MRCA) with another male in shared lines. 

There is also a second test of mitochondrial DNA (mtDNA) which follows the maternal line only — mother's mother's mother, and so on. This test can link you to others who share your exact maternal line, back to the earliest so-called "daughters of Eve." 

An excellent explanation of both these tests using a standard genealogical inheritance chart is found at


The goal of the TERRIOT Surname DNA Project is to confirm the descendance of the currently documented branches (with all spelling variants) from Jehan and Perrine Terriau through their sons Claude and Germain as listed in the 1671 Census of Acadia.

We would also like to find any descendant of Jehan, the mysterious brother of Claude and Germain, who was also listed in the Census of 1671 but was not present. Links with TERRIOTs (and variants) living today in France are a distinct possibility, and would be welcome. We also want to explore the relationship, if any, with the THERIAULT dit Grandmaison line in Québec. We hope to make it easy for anyone to find and prove a TERRIOT connection in their male line. Any slight mutations will make distinguishing various branches a possibility. With more participants in the Terriot Surname DNA Project, we may be able to identify just when these mutations first occurred.

Another project sponsored by the Terriot Acadian Family is found in the Geographical Areas section of Family Tree DNA's web site, under "Acadia-Métis Mothers". We hope to find,  through testing of mtDNA, proof of the European or native American origin of several early Acadian women. Many of these purported "mixed-blood" women were married to Terriot men and so were mothers of TERRIOT lines. The correct French word for these women of mixed native and European ancestry is "métisses" (the feminine plural).


In the autumn of 2003, the 'Terriot Acadian Family Society' organized six male members of the organization with the TERRIOT name or variant to submit their DNA for testing. The results of these six tests would constitute the first benchmark for the Terriot Y-chromosome DNA. Each of the six participants already had genealogical documentation connecting their descendancy from Jehan Terriot, the progenitor of the family and the one man of the surname who came to Acadia from France around 1636. He appeared on the 1671 census as Jehan Terriau, age 70, with a wife and seven children listed. Only two of his sons apparently had children and passed on their father's Y chromosome to his grandsons. From them, that Y chromosome has been passed down fifteen generations to perhaps more than 100,000 living persons today with that surname.

After the results of the first six volunteers were posted and compared, it was clear that they were all  confirmed as sharing the same Y-chromosome DNA and thus, the same Most Recent Common Ancestor which is Jehan Terriau (Terriot) according to their documented genealogy. With this base of six matching sets of DNA, a 'benchmark' was established for the Terriot family. Henceforth, this benchmark can be used to determine whether an individual who has submitted his DNA for testing, is a direct descendant of the Terriot family. 

It is interesting to note that two small mutations were noted on one Louisiana line. We hope to discover where this change first occurred. Please note that this candidate is confirmed a descendant by the other exact matches on 23 out of 25 markers.

With our genetic benchmark in place, the first to use it  was in September 2004. The individual was adopted, but had documentation that his biological father was a Theriault. Happily, his DNA matched perfectly with the benchmark DNA. Another request has just been received, and is another match. With broader announcements, we expect to increase the number of results in our benchmark.

   Figure 1. Current Coverage of the Terriot Surname DNA Project
Click on this graphic to view the diagram...The Great-Branch Lineage Chart of the Terriot family shown at left identifies the branches that have been tested at this time. (left click on the chart to open for viewing. To print a copy of the chart, click here.)

If you are a male THERIOT and descend from Joseph [47]1 (especially if you are a descendant from his grandson Michel Eloi THERIOT), or Olivier [73], the shoemaker from Nantes, or Pierre [56] (through his son Pierre-Marie), or Joseph [19]'s sons Thomas [61] or Paul, please consider participating in our Terriot Surname DNA Project. If you descend from Joseph [47] through his son Pierre, we would like to have more participants to pinpoint exactly where in the lineage the mutations have occurred which were found in one of the Louisiana Theriot test results in the original benchmark. These areas of interest are highlighted in yellow on our Great-Branch Lineage Chart.

1In accordance with the conventions of our Jehan Terriot Archive, the numbers in  brackets [ ] are the RIN (Record Identification Number) assigned to an individual in the forthcoming revision of our Archive, version 2005.1. In each case, the numbers are consistent with those assigned by Stephen White in his 'Dictionnaire Généalogique des Familles Acadiennes'. 


The firm, Family Tree DNA which  we chose for our Surname DNA project is associated with the University of Arizona's genetic testing laboratories. In their services, the firm offers participants a reduced fee for conducting the Y chromosome test for paternal direct lines. (See the 'COST' section below.) They will also store each sample for 25 years, and if you later choose to do a more comprehensive test,  they will conduct the additional testing using your original DNA specimen and without requiring any additional specimen to be submitted. 


To join our surname DNA Project, go to Family Tree DNA and then select the "Surname Projects" option on the left. In the search field, enter Terriot (or Theriot, Theriault, or other variant), and you will find a form for submitting your personal information. After you submit your information, the company will send you a testing kit, with return envelope.

You can also scroll down to "Geographical Projects" and search for "Acadia—Métis Mothers" if you wish to submit mitochondrial DNA for our female-line project.

Direct links: 


Fees for Y chromosome male surname tests represent a reduction when in a surname project. Only males can take this test. 

  • 12 markers      $99 (group price); lowest  level, upgrade later  to 25 markers for $90
  • 25 markers      $169 (group price); upgrade later to 37 markers for $59 
  • 37 markers      $229 (group price)
  • For mtDNA (mitochondrial) female-line-only test which determines the haplogroup (ancestral origin) and permits matches with others. Both males and females can take this test, but it only shows the maternal direct-line. ($149   when part of a group study)

    Please note that all test kit envelopes require a $2 shipping and handling fee added to above rates.


    The DYS numbers below prove that all the DNA submitters to our project up to now share a common ancestor, since the markers match nearly perfectly. The first vertical column after the names is marked "*Haplo," which is short for Haplogroup. For our Surname Project this is only a prediction, based on the information volunteered by the test candidates when they filled out their personal forms. Because Jehan Terriau came originally from France, this would place his DNA group among those most common in western Europe, namely R1b. If any kit submitter wants to know his haplogroup more definitively, an SNP confirmation test can be added to confirm the haplogroup.

    Mutations can occur in the number of alleles (or repeats) shown at any given marker number. Two of our DNA submitters show these mutations, which are marked in purple and italics. The two mutations noted in the one Louisiana Theriot test are at DYS #458 (in red to indicate a faster mutation rate that average on this marker) where his test shows a "17" rather than a "16" on the others. The other variant is at DYS #447, where he has a "26" rather than a "25."

    There is also a mutation of one number in another case, at DYS #392. None of these variants affect the conclusion that all the testees so far are directly descended from the same progenitor.

    Figure 2. DNA Test Results for Individual Members of the Terriot Family




    Please contact Karen Theriot Reader, our Project Administrator at  for more information.