Y-DNA Project

Theory (beginners)

All newcomers are strongly advised to visit the testing agency's excellent website (www.familytreedna.com) and watch the introductory online video and avail of the online tutorials to get a basic grasp. This is, by far, the fastest and easiest way to learn the basics.

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, Y-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. Please note that this particular DNA test is for men only! Don't blame us; Mother Nature makes the rules! Men who do not bear the Flannery surname, and women who bear the surname, may all participate vicariously by nominating a Flannery brother / uncle / cousin to be tested on their behalf.

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!

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-markers 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-markers test in November 2001, and this has been adopted as the global standard (entry level). The 37-markers test was launched in December 2003, and this appears to be discriminating enough to differentiate individual family lines within a related group. The 67-markers test was launched in May 2006, but the additional markers will not be useful until mutation rates have been established for them.

It should be obvious at this point that Y-Chromosome testing was "emerging science" when we started our project in 2003. Since that date, numerous projects have been verified using conventional research run in parallel and there is now great confidence in the reliability of the test results.

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 37 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 occurance of the most recent common ancestor of two people.

Does It Work?

The O'Gara Clan and the Kavanagh Clan 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 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 DNA projects :-

  • Roper Surname Project

  • Mumma Surname Project

  • MacGregor Surname Project

    The following links provide further information to suit all levels. Don't forget to contact the team if you have any queries about any aspect of the project.

    Theory (intermediate) | Theory (advanced)

    Project | Reports | Tabulated Results | Charts | How to take part