Cumann na gClann Ui Thighearnaigh

Tierney Y-DNA Project



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Background   Fingerprint Testing   Why Take Test   Does it work   Cost   Who Can Apply   Privacy   Conditions   How to Join  

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Background Information

The human body has 100 million million cells. A cell is the basic unit of structure in living things. Chromosomes are tiny bodies in a cell which carry the genes. A gene is a piece of DNA (deoxyribonucleic acid) which carries the hereditary information.

Only males have the Y-Chromosome which is passed from father to son usually in identical form from one generation to the next. Occasionally, a change (which is called a mutation) occurs between a father and son. Some families have more changes than others. As surnames are passed from father to son through the generations, DNA testing is confined to men with the same surname (or phonetically similar surnames).

DNA testing is not an all-male preserve. Female lineage can be traced using Mitochondria instead of the Y-Chromosome, but the patronymic nature of Irish surnames means that this form of testing is not useful in Irish genealogy.

DNA may be sampled in a number of ways. The easiest method is to take a minute sample of skin cells from the mouth by gently brushing the inside of the cheek with a small sterile brush. The process does not hurt. The test is self-administered using what looks like a travel toothbrush which is then popped into the post for analysis. A blood sample is not required!

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DNA Fingerprint Testing

The familiar double-helix model of DNA was developed by Francis Crick & James Watson in 1953, and the DNA fingerprint was discovered by accident in 1985 by Alec Jeffreys.

The accuracy of the Y-Chromosome test, and reliability of the results, is directly related to the number of reference points (called markers) used in the analysis. The lowest useful resolution is 12 markers, and this was the world's first commercial DNA test developed by FamilyTreeDNA in the U.S.A. in March 2000. However, whilst the 12 marker test easily differentiates between Africans, Eastern Europeans etc., it lacks the fine resolution required to differentiate between the more recently arrived Western Europeans. Consequently, FamilyTreeDNA launched the 25 marker test in November 2001, and this was followed by the 37 marker test. This has been adopted as the global standard. In more recent times FTDNA have added a 67 Marker test to their facilities.

It should be obvious at this point that Y-Chromosome testing is an emerging science!

The point in the Y-Chromosome where the marker is tested is called a DYS number. The test value assigned to each DYS is called an STR (Short Tandem Repeat).

The raw data table of 25 DYS STRs is called a haplotype. Exact or nearly exact matches of data establish the haplotype of the common ancestor. The next most important factor is the MRCA number (Most Recent Common Ancestor), which is the estimated number of generations to the occurrence of the most recent common ancestor of two people.

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Why Take The Test?

Our co-ordinated project of testing aims to achieve the following goals:-

  1. To identify three distinct DNA groups to verify the currently held theory that modern-day Tierneys are descend from three distinct and unrelated septs (Ó Tierney of Cearra in County Mayo, Ó Tierney of Fearnmhaigh an ancient kingdom in Ulster barony in County Mayo, and Ó Tierney of Meath – West Meath in Leinster).
  2. To identify the sept(s) from which the O’Tierneys of North Tipperary, Galway and Limerick are descended.
  3. To assist all participating clan members to identify their personal origins, both by connecting to other members and by connecting to one of the three distinct septs.

There are absolutely no guarantees that all of our goals will be achieved.

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Does It Work?

The O'Gara Clan and the Kavanagh Clan and many other Irish Clans have already embarked on Y-DNA projects, and the results to date have been very encouraging. We are grateful to Maura O'Gara-O'Riordan of the O'Gara Clan, and Fergus Kavanagh of the Kavanagh Clan, both serving directors of The Clans of Ireland Ltd., for sharing their knowledge and bringing us up to speed on this exciting opportunity.

Check out the following websites for additional information on other successful surname Y-DNA projects :-

·  Roper Surname Project

·  Mumma Surname Project

·  MacGregor Surname Project


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How Much Does It Cost?

Technology has a price, of course. We have shopped around, and conclude that FamilyTreeDNA offer the best value. By proceeding as a registered group - as opposed to independent individuals - we can avail of a discounted group rates which are as follows: -

12 Marker Y-DNA* test $99 + postage.

12 to 25 marker upgrade $49, 12 to 37 Marker Upgrade$99, 12 to 27 Marker Upgrade $189.

25 Marker Y-DNA* test $148 + postage.

25 to 37 Marker Upgrade $49, 25 to 67 Marker Upgrade $148.

37 marker Y-DNA* test $189 + postage.

37 to 67 Marker Upgrade $99.

67 Marker Y-DNA* test $269 + postage.

* Archival storage of your DNA for 25 years is included with all tests.

The cost is billed in U.S. Dollars as the Testing Agency and Test Laboratories are situated in the U.S.A.

Something to consider! The greater body of opinion would seem to indicate that a minimum 25 Marker test is best. The more markers you test the more accurate the end result. For example on a 12 Marker test you could match with someone 100% and think, 'Great I have found a cousin'. However, there may be numerous Marker differences if both opt for a higher Marker test and this may show that there is actually no relationship at all. So, as stated the more Markers tested the more accurate toe results.

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Who Can Apply For The Test?

It is anticipated that very many Clan members will be willing to participate in the project. Test results (months, years or even decades hence) will be added to build up the database. The greater the number of test results, the greater the chance of achieving our stated objectives.

Members who do not bear the Tierney surname, and female members who bear the surname, may all participate vicariously by nominating a male Tierney surname-bearing known relative to be tested on their behalf. We shall facilitate all members who wish to participate in this way.

What About Privacy?

All participants (and their DNA samples) are assigned code numbers, and the project co-ordinator is the only person able to match names to results.

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Are There Any Conditions?

In order for the project to run smoothly, we have established a few basic ground rules :-

· We have adopted the 25 marker test solely [and do not encourage members to take the 12 marker test.] This is because the 12 marker test does not provide sufficiently detailed information. The new 37 marker test is under review; however the 25 marker test can be upgraded to a 37 marker for an extra fee of U.S. $59 (see costs section above).

· We bestow honorary life membership on all participants. This is because each and every test result helps us to form a vital core of information for present and future members.

·  All participating clan members must sign a waiver permitting their information to be shared within the clan. Please note that summary information shall be published, but personal information shall not be passed outside the clan.

· All members who participate must pay their own test fee (U.S. $169 + postage) or any such revised test fee introduced by the testing agency in the future (inflation etc.). Payment must be sent directly to the testing agency, not to The Tierney Clans Society.

·  Any results which might give rise to embarrassment shall be kept strictly confidential, and shall not even be shared within the clan.


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How To Proceed?

The Tierney Clans Society Y-DNA Project commenced in October 2004 and is fully underway. We are now seeking participants to our project.

If you are interested in participating, then please register online at the testing agency's website ( Alternatively, you may contact the Tierney Clans Society Y-DNA Project Co-ordinator (Cahir Tierney) directly by either email or post (Naomh Antoine, 53 Ard Aoibhinn, Athenry, Co. Galway, Ireland). Please be sure to give your full name and postal address. You will then be sent a waiver form to complete and return before your test kit is issued.

Many of us regard this exercise as a unique opportunity to buttress previous research (based on primary and secondary sources) with definitive scientific evidence. We hope that the majority of our members recognise the importance of this project, and support the Tierney Clans Society by participating.

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Last updated Eanáir 2007.