A Basic Guide to Y-DNA Testing for Ireland Projects

Introduction

A man’s passes only to his sons and never to his daughters. Historically, a man passed his to his children and until recently it was presumed married women took on their husband’s names and their children inherited the father’s surname. Thus, boys passed on both the Y chromosome and surname as a package deal. Genetic testing for family history and genealogy utilizes this correlation between a surname and the Y chromosome.

Surnames have been around for about 1000 years, so compared to a man’s DNA a surname is a new innovation. A given surname may have many paths to its derivation. There are numerous circumstances through which a man can acquire his surname. A surname DNA project looks at what history says about the surname and tries to confirm (or refute) that history, provided there are a sufficient number of DNA samples with which to work.

It is common for the members of a surname DNA project to have numerous , and for a given surname project to find that it has a close relationship with other surnames. For example, there could be Mannings in an O’Brien project, or Magraths in an O’Sullivan project.

Nomenclature

Most of the DNA on the Y chromosome does not recombine. However, the DNA in this non- combining region may mutate. A base pair is a pair of proteins which construct the DNA helix, and a change to a single base pair is also called a Single Nucleotide Polymorphism (SNP or “snip”). This DNA has a very slow mutation rate. A set of one or more such mutations in this region define a . A haplogroup then can simply be thought of as a branch of homo sapiens, or a descendant branch off the original male ancestor. Over many tens of thousands of years, a haplogroup may have mutated into a few well-recognized variations and such a variation is called a . (A subclade is analogous to a branch growing off the trunk of a tree or a twig growing off a branch.) A deep test of SNPs determines a man’s haplogroup and subclade.

Also on the Y chromosome are regions of what is called “junk” DNA. This DNA contains repeating sequences of DNA called Short Tandem Repeats (STRs). Mutations of these STRs are random and occur at an average rate of perhaps 1 per 500 generations. That means some mutate far more frequently and some mutate far less.

A STR mutation will result in the STR losing or gaining a sequence. A genetic Y-DNA test looks at the STRs. The value of a particular DNA sequence is called an allele. A specific pattern of alleles define a man’s . This pattern of mutations which otherwise serves no value is like a fingerprint identifying a family branch.

Groups of men with the same haplotype and belonging to the same haplogroup are likely to share a relatively recent common ancestor. Two men with closely matching test results can then work

Susan J. Barretta – revised November 14, 2012 Thanks to Robert D. McLaren for his assistance Page 1

A Basic Guide to Y-DNA Testing for Ireland Projects together to determine their Most Recent Common Ancestor (MRCA). The more of these STRs that are tested, the better the results will serve the tester when he wants to determine his shared common ancestry with other testers. Working on the genealogy and the paper trail of ancestry is very important to achieve this.

Unique emerge as more markers that are tested. Specific mutation patterns can appear in different , analogous to the way that similar physical features such as red hair can occur in people from different families. Therefore the genetic Y-DNA test cannot conclude with absolutely certainty what a man’s haplogroup is, though it can make predictions. When a man falls into a particular test group and that man has had a haplogroup test, those who match this tester will then know their haplogroup with about 95% certainty. In the control panel of your Y-DNA test account, the haplogroup of your test result may be blank and that is probably because you didn’t take a haplogroup test. But you may still know your haplogroup from your STR results and by comparing your test results to others.

Haplogroup Labeling Conventions

A haplogroup is labeled with a capital letter. Haplogroups are refined by , and these are shown by numbers and lower case letters following the initial capital letter. The entire word serves as a label for a specific subclade. E1b1b and R1b1b2 are labels representing certain subclades. These subclades split off from older haplogroups based on E and R, respectively. Sometimes these subclade labels get long and thus the label for a particular subclade may get remodeled into a new short label.

The boundary between what constitutes a haplogroup and what constitutes a subclade gets blurred, and you will see a subclade of an old haplogroup in itself called a haplogroup.

In your list of Y-DNA test results, you may see a column called Terminal SNP which is the most refined sub-branch of the Y-DNA tree into which somebody has been classified. SNP labels start with a capital letter followed by a number, e.g., L21 or P30 or M253.

Haplogroups of Europe and Ireland

See “Origins, age, spread, and ethnic association of European haplogroups and subclades” under References for maps and illustrations of the haplogroups listed below.

Haplogroup R1b split off from of the R1 haplogroup about 22,000 years before present (YBP). It is by far the dominant Y haplogroup of Ireland and Northern Ireland. In northeast Ulster and in the area of Leinster extending south from Dublin, the frequency is perhaps 60%. Everywhere else on the island the frequency is considerably greater, as well as in northwestern Scotland, Cornwall and Wales, and along the shoreline from northeastern Spain up through France.

Susan J. Barretta – revised November 14, 2012 Thanks to Robert D. McLaren for his assistance Page 2

A Basic Guide to Y-DNA Testing for Ireland Projects

According to Wikipedia, a major branch of R1b that occurs with high frequency in the British Isles was labeled R1b3 from 2003 to 2005; R1b1c from 2005 to 2008; R1b1b2 from 2008 to 2011; then it was labeled R1b1a2 and is now short-labeled R-M269.

Haplogroup I1 is associated with Norse, Scandinavian and Germanic ancestry. It occurs in Leinster, encircling Dublin in the historic region of The Pale, at about a 10% frequency, and about half that for the rest of Ireland. It, too, occurs in England, Scotland, and Wales at about the same frequencies.

Haplogroup I2, associated with Sardinians and Basques, occurs at low frequency (1% - 5%) through most of continental Europe; through the midlands and eastern part of England and an eastern part of Scotland. In Ireland the same low frequency occupies a thick band from northeast Ulster to southwest Munster, bypassing Donegal, Connaught, and much of Leinster. Haplogroup I2a2, associated with pre-Celto-Germanic people, occurs in low frequencies ranging from 1-2% in southwest Cork and Kerry, pushing up through the midland counties, to a 3-4% frequency that caps Ireland from west Kerry, up through the Connaught, through Ulster, and then along an eastern coastal band stretching down to Waterford. One further subclade of I2c, thought to have come from the Rhine region, appears constrained to the British Isles and some Germanic areas.

Some other haplogroups occurring at very low frequencies in Ireland are R1a, G, J2, and E1b1b.

STR Labeling Conventions

Each STR scrutinized by a Y-DNA test is called a marker and has an identification number. That ID number is preceded by letters that characterize the nature of that STR. A STR label starts with D (for DNA), then Y (for Y chromosome), and is then followed by S (for a single segment), Z (for a number of repetitions in the same area), or F (for repetitions spread out over the chromosome). STR numbers are therefore preceded by DYS, DYZ, or DYF.

The label of a STR of particular importance may also be remodeled, so references to that STR may not follow the aforementioned STR naming convention.

The Atlantic Modal Haplotype

The Atlantic Modal Haplotype (AMH) is a package of specific alleles that sometimes appears in haplogroup R1b, with the highest frequencies in males from Spain, Portugal, Great Britain and Ireland.

In the literature you may see discussion of the Atlantic Modal Cluster (AMC), which includes slight mutations off the AMH. You may also see discussion of a Western Atlantic Modal Haplotype (WAMH), which is a 12 marker refinement by Family Tree DNA that further differentiates the AMH. Since WAMH testers will have a great many matches, they should

Susan J. Barretta – revised November 14, 2012 Thanks to Robert D. McLaren for his assistance Page 3

A Basic Guide to Y-DNA Testing for Ireland Projects upgrade their Y-DNA test result to a greater number of markers to make it easier to find matches with more recent shared common ancestry. Commonly Occurring Haplotypes of Ireland and Munster

Y-DNA projects are looking to Irish history and trying to reconcile that history with the haplotypes that they see in the test population. Some of the major ones are listed here.

Irish Type I or northwest Irish, was identified in a Trinity College study. It is affiliated with Ui Neill. R-M222 is of high interest.

Irish Type II or south Irish, was identified by Dr. Ken Nordtvedt and is concentrated in Munster. It is characterized by several deviations from AMH plus four other alleles occurring in much higher frequencies than in AMH. Many Eoganacht sept surnames (e.g., Sullivan, Lynch, Collins, Donovan) appear in this grouping. R-L21 is of high interest.

Irish Type III or Dalcassian, researched by Dennis Wright, identifies STR markers with high frequencies in counties Clare, Tipperary, and Limerick. L-226 is of high interest.

Irish Type IV, or continental, also identified by Ken Nordtvedt, appears to be scattered in Ireland and a part of western Europe. Because of disparate surname sources in this group it has been particularly difficult to hypothesize who a common progenitor might have been.

There are many Irish Y-DNA projects, looking at provinces, regions, septs, and surnames. Refer to the individual projects to determine what the goals of the project are. The project will state what it anticipates and finds as its members are grouped according to their alleles. Some links to Irish projects are listed under References.

Steps and Distance

When you look at your matches in your FTDNA account, you’ll see people who match exactly; who are one step away; who are two steps away, and so forth. When you compare the values of the same marker between two testers, the number of steps is the difference (absolute value) between the markers. Therefore if the value of marker Z in Tester #1 is 13, and the value of marker Z in tester #2 is 15, the absolute value of the difference is 2 so there is a 2-step mutation between them.

The distance between two testers is the sum of the absolute values of the differences between all the corresponding markers.

Y-DNA Testing

How many markers to test is up to the tester, though generally the more the better. A minimum of 67 markers is normally recommended, and it is possible to upgrade the results with more Susan J. Barretta – revised November 14, 2012 Thanks to Robert D. McLaren for his assistance Page 4

A Basic Guide to Y-DNA Testing for Ireland Projects tested markers at a later time if necessary. (A 37-marker test leaves too much uncertainty if there are, say, three or four mutations between two testers.)

The following table, borrowed from FTNDA, shows the maximum number of generations back a MRCA lived with a 95% probability, when two testers match all their markers.

This means that there is a 5% chance that the MRCA may fall beyond the ranges listed below. Also note that mutations can and do occur, and there may be differences even between brothers.

Matching markers MRCA 10 / 10 within 72 generations 12 / 12 within 47 generations 25 / 25 within 13 generations 37 / 37 within 7 generations 67 / 67 within 6 generations 111 / 111 within 5 generations

Susan J. Barretta – revised November 14, 2012 Thanks to Robert D. McLaren for his assistance Page 5

A Basic Guide to Y-DNA Testing for Ireland Projects

References

Y-DNA Testing http://www.familytreedna.com/faq/answers.aspx?id=41

European and Irish Haplogroups

Origins, age, spread, and ethnic association of European haplogroups and subclades http://www.eupedia.com/europe/origins_haplogroups_europe.shtml http://en.wikipedia.org/wiki/Atlantic_Modal_Haplotype http://www.isogg.org/wiki/Western_Atlantic_Modal_Haplotype http://freepages.genealogy.rootsweb.ancestry.com/~gallgaedhil/haplo_r1b_amh_13_29.htm http://familytreemaker.genealogy.com/users/o/d/a/Donald-K-Odair/FILE/0069page.html http://www.familytreedna.com/public/ulster/default.aspx http://southirish.com/ http://mysite.verizon.net/timdesmond/files/dna_southirish.htm http://www.familytreedna.com/public/MunsterIrish/ http://www.familytreedna.com/public/Eo%C2%B4ganacht%20septs http://www.familytreedna.com/public/Corca_Laidhe/ http://www.familytreedna.com/public/R-L21SouthIrish/ http://www.irishtype3dna.org/ https://sites.google.com/site/irishtype4/irish-type-4-sub-clade http://www.familytreedna.com/public/RL21WTY2009/default.aspx

A Y-Chromosome Signature of Hegemony in Gaelic Ireland. Identifies a signature for descendants of Niall of the Nine Hostages. American Journal of Human Genetics. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1380239/

Insights into the O’Neills of Ireland from DNA Testing. Journal of . http://www.jogg.info/22/ONeill.pdf

Susan J. Barretta – revised November 14, 2012 Thanks to Robert D. McLaren for his assistance Page 6