Friday, 1 August 2025

How to analyse each genetic group in a Y-DNA Surname Project - a rough guide for Admins

You have a Surname DNA Project at FamilyTreeDNA. You have grouped your project members into a variety of genetic groups, based on the principle that, in any given group, the members appear to be related since the emergence of surnames (roughly 1000 AD in Ireland and 1200 AD in England). So how do you go about analysing each group and reporting your findings to your project members?

Here is the approach that I use with my various surname projects. My focus is on Irish surnames specifically, but this process can be adapted for surnames of any country. What I describe below is only one way of approaching the question, and other project administrators will have different approaches or variations on the one below, but hopefully this article will give you an idea of how you could approach the topic of analysing each genetic group within your project. Feel free to take what you like, adapt it for your own particular circumstances, and leave the rest. And if you have a better way of doing something, leave a short description in the Comments section below - I'm always on the lookout for hints, tips & shortcuts.

Before you start ... lay the foundations

Prior to starting the project, it is worthwhile exploring three different aspects of the surname (and writing up your findings as a blog post or article for your project members to read - I use Google Blogger because it is free and relatively easy to use). Here are the three topics:

1) Surname Distribution Maps - these give you a good idea of where the surname is particularly concentrated within the world. And you can look out for these locations among the EKAs (Earliest Known Ancestors) of your project members. For Irish surnames, maps based on Griffiths Valuation (mid-1800s) are available via John Grenham's website (subscription) and Shane Wilson's website (free). Barry Griffin's website (free) offers maps based on the 1901 & 1911 censuses. Here are some useful links, but you could also ask ChatGPT (or other AI engines) for more information or for Maps of non-English surnames:

2) Surname History - various surname dictionaries exist and these can give a useful account of where a particular surname arose, what type of surname it is (e.g. patronymic, locative, occupational, etc), if it has a particular meaning, if it is single origin or multi-origin, and what other surnames may be associated with it. This information has implications for your DNA Project because it may give you clues as to how many genetic groups to expect, which of them are likely to be the largest, and where the ancestors of group members are likely to come from.

Useful surname dictionaries include the following:

  • Woulfe's surname dictionary (Irish Names & Surnames): a useful searchable digital version is available on the Library Ireland website and the original 1922 edition is on Archive.org.
  • McLysaght's surname dictionary spans several discreet books but none of these are available online and all are currently out of print. They can be found in libraries and second-hand bookstores (but I find Woulfe's dictionary more informative):
    • The Surnames of Ireland. 1957
    • Irish Families. Their Names, Arms and Origins. 1957
    • More Irish Families. 1970
  • the "Irish Names" section of John Grenham's website (Irish Ancestors) is also helpful.
  • The Oxford Dictionary of Family Names in Britain and Ireland is currently available for free as a Kindle edition from Amazon.

You can read some useful examples below of how surname dictionaries can help set the expectations for your surname project:

3) Medieval Genealogies - it is helpful to know if your surname of interest is associated with a particular clan, and if there is a medieval genealogy available for the "royal" or chieftain lineage of that clan. A useful starting point is O Hart's "Irish Pedigrees; or, The Origin and Stem of the Irish Nation" because the 1892 edition is available as a free searchable digital version on the Library Ireland website. However, O Hart's version is not always the most reliable and if you plan on publishing your research in a scientific journal, you would need to consult other important sources for Irish Medieval Genealogies, which include:
  • Bart Jaski's genealogical tables (available as a 72-page pdf document)
  • the Ó'Cléirigh Book of Genealogies by  Cú Choigcríche Ó Cléirigh (O'Clery). A pdf version is available to view on JSTOR here and can be downloaded if you have an account. See also this Wikipedia article here. 
  • the Great Book of Genealogies (Leabhar Mór na nGenealach) was edited from the original (1649-1650) and published in 2004. It comes in 5 heavy volumes and costs about 600 euro. It has not been digitised and is not available online, so you would probably need to consult it at a specialist library. The original manuscript (in Irish) is available online here. See also this Wikipedia article for further information.
  • a list of key manuscripts containing Irish medieval genealogies can be found on this Wikipedia page here - some have links to online versions. And another Wikipedia page contains a list of medieval Irish manuscripts that may be relevant to your research.
  • if you are researching a particular surname, ask ChatGPT what manuscripts it would recommend consulting.

Key question to address in your analysis of each group ...

When we come to analysing each group in turn, my starting point is a series of seven questions:

  1. What is the dominant surname variant in the group?
  2. How old is the group? How long have they been carrying the surname?
  3. What are the chances of a Surname / DNA Switch (SDS; a.k.a. NPE, Non-Paternal Event)?
  4. Is there any evidence of an SDS / NPE?
  5. Where is the group from? 
  6. What is the branching structure within the group? 
  7. Can we connect the group to the Irish medieval genealogies?

Let's address each question in turn.

1. What is the dominant surname variant in the group?

This is important because some surname variants can be localised to a specific area. And this can signpost project members to a particular set of records. Some examples are given below (summarised by ChatGPT ... and thus to be taken with a pinch of salt, but you get the idea).

2. How old is the group? How long have they been carrying the surname?

In order to calculate this, at least two people with the relevant surname need to have tested. If they have both done the Big Y test, then they will appear on the Time Tree, and will have a TMRCA estimate (Time to Most Recent Common Ancestor) via the "Scientific Details" tab on the Discover feature. This age estimate tells you roughly how long the name has been carried by the ancestors of the two members of this group. 

There are several caveats to be aware of.

  1. These age estimates come with very large Confidence Intervals, usually several hundred years. In other words there is a large range, and even with lots of data, these ranges will never fall below +/-50 years. So the estimates will never be more precise than a one hundred year period. Let's take the 95% Confidence Interval for FT86146 as an example - 1238 CE (95% CI 1036-1402). This range stretches from -202 years to +164 years, a span of 366 years.
  2. The estimates will evolve over time as more Big Y data becomes available. For example, the TMRCA for BY35730 changed from 1029 AD (Jun 2022), to 885 AD (Aug 2022), then 802 AD (Sep 2022) and is currently 711 AD (Jul 25). So the central estimate has decreased by 318 years since mid-2022. 

The Take Home Message is: do not put a lot of faith in the central estimate - it will change over time, sometimes by several hundred years. And therefore be very wary about assigning a particular SNP marker to a specific named ancestor in the genealogies (medieval or modern) just because their year of birth is close to the central estimate.

In the example above, I had to say something along the following lines to the members of Group 3a in the O'Malley DNA Project: 

"The overarching DNA marker for this group was BY35730. The term overarching was thought to be appropriate because it encompassed all O'Malley men in the group. However, it now has a (current) age estimate of 711 AD (with a large range of 362-993). The central estimate (711 AD) has now moved outside of the Surname Emergence Era in Ireland (roughly 950-1150 AD) so we now need to consider if it would be more appropriate to identify a downstream DNA marker as being a more likely candidate for the overarching DNA marker for this group. And that now leaves one O'Malley man outside of the group. It may very well be that his O'Malley surname arose independently of everyone else in Group 3a." 

You can read more about this example here.

In the absence of at least two Big Y tests, you will have to rely on TMRCA estimates calculated solely on the basis of STR marker data. These can be hugely misleading, especially when there is a lot of Convergence present, and thus should be taken with a huge pinch of salt. These estimates can be accessed by using the Time Predictor tool (the last icon at the end of the row of the relevant match).  


In the example above, a Genetic Distance of 5 / 111 translates to a TMRCA estimate of 1650 CE (range 1450 - 1800). And thus, the common ancestor who passed on both the surname and the matching DNA signature was born about 1650 (approximately), and therefore the surname has been associated with this particular DNA signature for at least the last 375 years (approximately). What happened before that is not known at this point in time. Did they still carry the same surname prior to this? And does this go all the way back to the progenitor of the surname? or was there a Surname / DNA Switch (SDS; a.k.a. NPE, Non-Paternal Event)?

3. What are the chances of a Surname / DNA Switch (SDS / NPE)?

Given that the average rate of an SDS / NPE is 1-2% per generation, then the chances that such an event occurred on a direct-male-line over the period of the last 1000 years is 33-55%, calculated thus: 

  • let's assume 25 years per generation, so in 1000 years (i.e. 1000 AD to 2000 AD) there are 1000/25 = 40 generations
  • the probability of having no SDS / NPE in 40 generations at a 1% incidence rate is 0.99^40 (i.e. 0.99 multiplied by itself 40 times) = 0.669 (i.e. 66.9%) ... and therefore the probability of having at least one SDS / NPE is 1 - 0.669 =  0.331 (33.1%)
  • with a 2% incidence rate, the calculation is 1- (0.98^40) = 1 - 0.446 = 0.554 (55.4%)
  • and thus the overall incidence rate is about 33% - 55% over the 40 generations

If instead we use 30 years per generation, then the rate is about 28% to 49%. 

So (for ease of explaining to others), I usually round the overall estimate to 50% and tell people that everyone has a 50:50 chance of an SDS / NPE on their direct male line over the last 1000 years.

So if the TMRCA estimate is 1650 (as in the example above), then this leaves 650 years unaccounted for (i.e. 1000 AD to 1650), which is 26 generations (@25yrs per gen), then the probability calculation is 1 - (0.99^26)% to 1 - (0.98^26)% = 23.10% to 41.26%

Or you can simply ask ChatGPT: what is the risk of an NPE on the direct-male-line assuming the following - an NPE rate of 1-2%, a time period of 650 years, and 25-33 years per generation?

In the example, it is useful for project members to know that the chance of an SDS / NPE between 1000 AD and 1650 AD is in the range of 23-41%. This braces them for the distinct possibility that the surname on their direct-male-line may have been a different surname to that which they carry today, but the switch probably happened some time before 1650.

I discuss the various potential reasons for a switch in two articles, one dealing with more modern causes and the other with more medieval causes.

4. Is there any evidence of an SDS / NPE?

Various pieces of evidence point to the likelihood that an SDS / NPE has taken place on a project member's direct-male-line.

1) the project member is already aware of it and has given you all the relevant details.

2) the project member has supplied information about their EKA (Earliest Known Ancestor) and the EKA has a different surname to the project member.

3) the participant does not match any known test-takers with the surname of your surname project.

4) none (or few) of his STR matches have his surname. In fact, some other surname may predominate.

5) the project member has been placed on the Time Tree but is surrounded by people on adjacent branches who all have the same surname, but it is not his. See the MacPherson / O'Malley example below and here (from the Group Time Tree for the M222 Project).

If you can think of any other indicators, please leave a comment in the Comments section below.


5. Where is the group from?

This is a really important question to answer for the individual project member as it may signpost him/her to a specific record set for further documentary research. 

Ideally it would be great if each project member supplied their EKAs birth location, including country, county, and town / townland. In time we might be able to associate people from a particular town or townland with a specific DNA marker. 

Assessment of the surname in Surname Dictionaries and Surname Distribution Maps will have given you some idea of where to expect some genetic groups to come from. Evidence for a group's likely ancestral origins can be assembled by several different methods.

1) some people include ancestral location with their Earliest Known Ancestor details (Account Settings > Genealogy > Earliest Known Ancestors > Direct Paternal Ancestor). This is displayed on the public Results Pages of any projects to which they belong, and on the Group Time Tree, and on their Profile if they appear on the list of matches of your project members. But many people only have their EKA name, and sometimes birth & death dates. And only 50 characters are allowed in the Direct Paternal Ancestor field, which may not be enough to include birth location.

2) alternatively, some people have included their EKA birth location in the Paternal Ancestral Location field (Account Settings > Genealogy > Earliest Known Ancestors > Paternal Ancestral Location). But this is NOT displayed on project Results Pages or the Group Time Tree. To access this data, Admins can log in to their GAP pages, go to Reports > Member Reports > Paternal Ancestry, sort the members by "Sub Group", and scroll down to the relevant group. This is what the information looks like ...


You can see from the above that information about EKA birth location is sometimes not entered at all, sometimes in one field, sometimes in the other field, and sometimes in both. And thus sometimes the data is visible on the public Results Page (data from  the Direct Paternal Ancestor field) and sometimes it is not (data from the Paternal Ancestral Location field).

Admins should also be aware that the titles of the columns above and the fields from where the data is obtained are not exactly the same i.e. the Direct Paternal Ancestor field feeds into the Paternal Ancestor Name column, and the Paternal Ancestral Location field feeds into the Map Location column.

Lastly, this particular approach only works for people who are in your project. You cannot get this information for people who are outside of your project because you do not have access to their data. 

Admins should encourage project members to enter EKA birth location information because many testers will not realise the importance of doing so. Admins can help their project members do this by emailing them and providing instructions on how to do so (include a link to this explanatory article if you like). I would suggest to recommend putting the EKA birth location in the Direct Paternal Ancestor field (which will allow it to be made public on the Results Page) and forget about the Paternal Ancestral Location field (which is not made public on the Results Page).

Alternatively, if you have their permission to do so, you can update this information yourself (but they will need to give you Advanced Access first by logging in to their account and going to Account Settings > Project Preferences > Group Project Administrator Access, then find the relevant project, click the pen icon on the far right of the row to edit the preferences, then scroll down through the text of the pop-up box to find the relevant Admin name, then in the Access column click on the drop-down menu and select Advanced).

3) email people and ask them for their EKA's birth location.

4) for members who have not displayed their EKA birth location, or simply don't know, you can look at the birth locations of their closest genetic neighbours. This can narrow down their likely ancestral origin to a country and even a county. 

If the test-taker has done the Big Y test, a first step would be to go to FTDNA's Discover page, enter their haplogroup, click on Time Tree, and assess the country flags that appear on the tester's branch and adjacent branches. You could also click on Country Frequency, and then Table View. This brings up a list of countries (and associated flags) and the number of tested descendants per country. Predominant numbers stand out and indicate the likely country of origin. 

The country flag is determined by the information the test-taker has entered in the Country of Origin field (at Account Settings > Genealogy > Earliest Known Ancestors > Direct Paternal Ancestor). Martin McDowell has made a helpful video about how to use and interpret this information here. One of the points that Martin makes in this video is using the Country Frequency "Table view" to determine the country of origin information for any specific haplogroup. This gives a very clear view of how many people have entered the info, and how many haven't (i.e "Unknown Origin" entries). 

You can also use the Ancestral Origins table (on the project member's Homepage, go to Results & Tools > Y-DNA > Ancestral Origins). Another option is the Matches Map feature on FTDNA (on the project member's Homepage, go to Results & Tools > Y-DNA > Matches Map, and select marker level in the top left). The latter two options have to be done member by member via their Homepage (potentially a time-intensive task), but can provide useful information that suggests a likely county of origin (as in the example below).


6. What is the branching structure within the group?

Defining the branching structure essentially creates a genetic family tree for the group. Any available genealogical data can be hung onto the branches like baubles on a Christmas tree. In effect, DNA markers become substitutes for ancestors when the genealogies run out (i.e. hit a Brick Wall ... which is typically around 1800 for Irish research).

This also emphasises the importance of trying to recruit people with extensive pedigrees to your project - determining their DNA branch will allow others to see if they too sit on the same branch and can therefore "piggyback" onto the known genealogy. 

A good example of this is the Royal Stewart project where it is estimated that over 80,000 people have benefitted from the Big Y tests of 4 specific members with extensive lineages.

There are several versions of the Y-Haplotree that help to illustrate the branching structure for a genetic group, but none of them are optimal. Here are the key differences:

  • Time Tree - this displays Big Y data only. It displays country of origin, but there are no surnames of test-takers, or EKA details. The big advantage of the Time Tree is that it displays all the known branches determined by Big Y testing.
  • Group Time Tree - this displays branches with both 1) test-taker surnames & 2) their EKA details. But not all known branches are displayed because a) test-takers have not reset their default display settings, or b) wish to remain private, so only a partial view of the Y-Haplotree is presented.
  • Classic Tree - this has all the branches, country of origin, rounded dates for TMRCA estimates, & SNPs per block ... but no test-taker surnames or EKAs.
  • Big Y Block Tree - this is not public and can only be seen by the test-taker or project Admin. It includes the full names of all matches, and their EKAs can be obtained by clicking on their name (twice). This also reveals the number of SNPs per SNP block and their names.
  • Public Y-Haplotree - this contains data from SNP Packs and single SNP tests as well as Big Y data. As a result, this has a bottleneck effect in that people who have only done SNP Packs or single SNPs will end up in big clusters on upstream branches. This can be misleading if you don't know what's going on, because it looks like some surnames "belong" on upstream branches whereas if the people had done Big Y testing instead of a SNP Pack, then they would have been moved to a more relevant sub-branch downstream. This tree can be accessed a) at the bottom of the FTDNA homepage under "Community", b) via the GAP pages (Reports > Genetic Reports > Y-Haplotree) and c) here. This tree can display test-taker surnames (switch to "View by: surnames") but only in a very limited way - this only happens if at least 2 people on a branch have exactly the same surname spelling.
The best way of visualising a specific genetic group would be to have a display of all the branches with all the test-taker surnames and their associated EKA details. To achieve this what I usually do is use the Time Tree as my starting point (it has all the branches that have been identified so far), take a screenshot of the relevant branch (and sub-branches), paste it into one or more powerpoint slides, and then manually add in the following:
  1. test-taker surnames & EKA details, including birth location - these can be gleaned from several sources:
    • your project's public Results Page
    • your Group Time Tree
    • the Big Y Block Tree (be aware that some of these will have their display options set to private and thus the diagram you are creating should only be used for analysis purposes)
    • the match lists of your project members who sit on the branches associated with this group (again, some of these will have their display options set to private)
    • a Google search for the SNP that characterises each branch or sub-branch (i.e. google: "FTDNA" and "SNP name" and "-Discover")
  2. TMRCA central estimates - obtained for each SNP from the Scientific Details tab on the Discover feature 
  3. number of SNPs in each SNP block - obtained from the Block Tree or the Public Y-Haplotree. Knowing this gives you some idea of the chances that further Big Y results might cause a split in any given SNP-block.
  4. relevant STR matches - these can be added manually to the diagram if there is clear evidence of a USP (Unique STR Pattern) that is likely to be predictive of a particular SNP-defined branch.
This visualisation (suitably privatised) helps project members see exactly where they sit on the genetic family tree for their group. It shows them who they are closely related to, and who they are not. This may help point them in a specific direction for further research in the records.

7. Can we connect the group to the Irish medieval genealogies?

The Irish medieval genealogies are the oldest in Europe. They extend back in time to the dawn of surnames (1000 AD or thereabouts), and before that to the advent of literacy in Ireland (600 AD or thereabouts), and before that into the semi-mythological past. 

However, there is a large gap between most Irish Brick Walls (around 1800) and the time when most medieval genealogies run out (about 1600, or beforehand). So one challenge is to bridge that 200+ year gap between 1600 and 1800.

Another challenge is to figure out which genealogies are accurate and which contain errors, or have been deliberately fabricated for sociopolitical gain.

DNA can help tackle these challenges and there are many instances where the DNA has either confirmed or refuted the veracity of the genealogies. For example, the O'Malley clan of Mayo do not connect genetically where one would predict them to connect based on the genealogies, so there is probably a longstanding error in the genealogies.

Trying to connect a particular genetic group to the ancient genealogies involves a painstaking process that calls upon a lot of data, much of it outside of your own surname project. It involves firstly building a CAST (Clan-Associated Surnames Tree) based on the medieval genealogies, and secondly a DAST (DNA-associated Surnames Tree) based on the Y-DNA data. The two trees are then compared (CAST vs DAST) to look for consistencies and inconsistencies. Consistencies lend support to the relevant portion of the genealogies, inconsistencies highlight likely errors in the genealogies. A description of the process can be found in two FTDNA blog articles, starting here.

If you have any comments or suggestions, please leave them in the Comments section below.

Maurice Gleeson
August 2025

My thanks to Martin McDowell and John Cleary for some suggestions and refinements to this article.




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Friday, 29 November 2024

Why are my DNA results missing?

Many people cannot find their Y-DNA results on the Results Page of the project they have joined. What's going on? Why are everyone else's results there but not yours? Why are they missing?

The answer is quite simple and you can easily fix it in 30 seconds. Just watch this YouTube video, or follow the instructions below.

Here is how you make your Y-DNA results publicly-visible ...

1) log in to your account at FTDNA

2) go to Account Settings (from the drop down menu when you click on your name in the top right)

3) click on the Project Preferences tab

4) scroll down to Project Sharing

5) click on the "Opt in to Sharing" button, so that it turns from grey (OFF) to dark blue (ON)


And that's it. Your Y-DNA results will be visible on the public Results Page of any projects you have joined at FTDNA. And you can reverse your decision at any time you want. Just click on the same button and it turns itself OFF. Simple!

Now your Y-DNA results are working for you in the background rather than being hidden away doing nothing. And this can benefit your own genealogical research as well as that of others.


Maurice Gleeson
Nov 2024





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Friday, 17 May 2024

Same Surname, Different DNA - some potential medieval explanations

Why are there so many different genetic signatures associated with a single surname? There are a multitude of reasons for why this may be so, and I discuss many of them in an earlier article here. 

However, in this article I want to focus on those potential causes that date back to the time of the Irish clans, prior to the Cromwellian conquest of Ireland. And this takes us back in time to a period prior to the demise of the Old Gaelic social system, a system that had been guided for centuries by a comprehensive legal system known as Brehon Law. (1) It recognised divorce, (some) equal rights for women, and defined offences and punishments in meticulous detail. The end of this system was signalled by a Proclamation of James I in 1603, which brought the Irish people under the "protection" of the English Crown.

Brehon Law operated in Ireland from Celtic times to the early 1600s, a period of over 2000 years. 
Brehons were arbitrators rather than judges, and the post was open to women and men.
(from https://www.courts.ie/history-law-ireland#brehon)

The Creation of Surnames

Brehon Law was well-established in Ireland by the time surnames were introduced (roughly 1000 years ago on average for the O surnames, and 850 years ago on average for the Mac surnames). Most Irish surnames arose from an ancestor's forename (e.g. descendants of Chief Conor became O'Connor). Some forenames were very common (like Conor) and thus the same surname arose in several different places, over several hundred years, but from completely different origins. And hence the progenitors had completely different Y-DNA signatures, and were not closely related to each other. There are at least six separate O'Connor clans/septs recorded in Woulfe's surname dictionary (2) ... and in fact there are 34 distinct genetic subgroups in the O'Connor DNA Project (so far). Thus, one explanation for different genetic groups being associated with the same surname is that many surnames had multiple origins, each of them distinct from the others, and each with their own unique Y-DNA signature.

In 1916 for example, T J Westropp, the famous antiquarian, described the Limerick O'Malley's as one of several "petty tribes ... rather families than septs". (3) And indeed, there may have been several of these "families" within the Limerick area as there are now 6 subgroups under L226 in the O'Malley DNA Project, all with recorded (or likely) Limerick origins. I'll give some more examples in relation to the O'Malley surname below.

The Translation of Surnames

Another possible explanation for different Y-DNA signatures being associated with the same surname is the anglicisation of surnames, a process aimed at forcing the Irish to conform to English culture that saw surnames being translated from the Irish language form into an approximate English language form. (4) This long-term process was a key part of the English colonisation of Ireland and picked up speed during the lifetime of Grace O'Malley (1530-1603) with the passage of new laws under Henry VIII (1537) that essentially labelled the use of the Irish language as a sign of opposition to the English Crown. (5) Serious problems arose during the process of translation. Some surnames in Irish with completely separate origins were anglicised to the same English version. Thus A and B both became anglicised to X.  And so genetically we find that there are X's with an A genetic signature and X's with a B genetic signature - two genetically distinct groups with "the same" surname (or variants thereof). 

Conversely, anglicization also helps explain why there are so many variants of the O’Malley surname. There are several examples on the public Results Page of people who have the same Y-DNA but different surname variants (Malley, O'Malley, Maley, Melia, Malia, O'Meally, etc).

The Switching of Surnames

There were several important aspects of the Old Gaelic social system that could explain why different genetic signatures became associated with (for example) the O'Malley surname.

Some people switched their surname to that of the chief as a sign of their loyalty or fealty. (6) In this way, surnames of less powerful families "gravitated" toward more powerful families. Such a process has been termed "surname gravity" by leading medieval Irish academic, Bart Jaski (see his GGI2019 presentation here). Grace O'Malley herself (the famous Pirate Queen of Mayo) may have commanded such respect even though she was never formally a clan chief. In her biography of Grace, (7) Anne Chambers describes how Grace became “a matriarch, not merely of her own followers and extended family, but of neighbouring clansmen, whose chieftains had either died in the numerous conflicts of the period, or who had abandoned their obligations to protect their dependent followers.” Some of these refugees may have adopted the O'Malley surname as a mark of respect, gratitude and loyalty to Grace.

Strangers could be given the honour of being adopted into a clan (a form of citizenship) in recognition of their contribution to the clan community. (8) Some of these may also have had the O'Malley surname bestowed upon them (for example).

Some marriages resulted in the husband adopting the surname of the wife, especially if she was of higher social standing than he was. An apt example of this is the case of Oliver Cromwell, who should really have been called Oliver Williams. However, in 1497, his great great grandfather (Morgan Williams) had married Katherine Cromwell, sister of Thomas Cromwell, chief minister to Henry VIII. Morgan and Katherine’s three sons took the surname Cromwell in honour of their famous maternal uncle. Thus, Oliver Cromwell carried the Cromwell surname but Williams Y-DNA. Some family members later reverted to the surname Williams in order to distance themselves from their contentious cousin, thus executing a double-surname switch. (9) 

Some women retained their maiden name. After the death of her second husband (Richard Bourke) in 1583, Grace O'Malley herself used her maiden name (Grany Ni Mailly) in her exchanges with Queen Elizabeth I who addressed her as such in her replies. (10)

Marriage, Sex ... and possibly Infidelity?

Under Brehon Law, marriage and sexual relations were approached very differently compared to today (and very very differently compared to the Victorian attitudes of 100-200 years ago). Ireland under Brehon Law was a much more sexually permissive society than one might imagine. It might be tempting to think that medieval society was like The Swinging Sixties, but better regulated and with everyone "on board", but promiscuity was frowned upon (at least female promiscuity), and was among the types of behaviour most frequently censured in women. (11) Furthermore, the introduction of inheritance by primogeniture (i.e. to the eldest son) led to a gradual change in sexual permissiveness in the 1600s, particularly for the landed classes. (12)

Most marriages were secular marriages based on the ancient customs - few people were married in church (13). Divorce was easy (for both men and women) and it was usual for the upper classes to have a string of different spouses. (13) This created an environment where the same surname could become associated with different types of Y-DNA.

Marriages usually started out as trial marriages for "a year and a day". (8) If at the end of the period, the couple were happy to continue as husband and wife, then they got legally married. But if they did not feel they could live together, they separated. Grace O'Malley famously did this with her second husband, shouting "Richard Bourke, I dismiss you" from the ramparts of his castle where she had installed herself and her followers, and locked him out. He can't have been very pleased to have lost a wife and a castle on the same day. (7)

Interestingly, if a couple separated at the end of the trial marriage, any children born to them during that time became part of the woman's kin (and thus presumably bore the name of her kin). (8) Thus if an O'Malley woman had a child during the trial period and then decided not to continue to legal marriage, the child would become an O'Malley but would carry non-O'Malley Y-DNA. Thus different Y-DNA was introduced to the wider O'Malley Clan.

Polygamy was allowed and it was common to have two or more wives. However, the term "wife" was more applicable to the first wife (the chief or principal wife). Subsequent wives had fewer rights than the first wife and might perhaps be more aptly considered as "concubines". (8,11,12,13)

The Brehon Laws refer to nine forms of sexual union. (11) The first three roughly equate with our modern concept of marriage, and the next four could be more akin to casual sex (referred to as "affinity" or "affiliation"), and the last two cover rape and insanity. The nine forms of sexual union are:

  1. when a man and woman get married and bring equal property or wealth to the marriage
  2. a marriage where the woman brings little or no wealth / property / goods to the marriage
  3. a marriage where the man brings little or no wealth / property / goods
  4. when a man visits a woman at her home, and with her kin’s consent
  5. when a woman freely goes away (elopes?) with a man, but without her kin’s consent
  6. when a woman allows herself to be abducted, and without her kin’s consent
  7. when a woman and man secretly visit each other, without her kin’s consent
  8. union by rape
  9. union of two insane people

Why was it necessary to create these categories of sexual union? The reasons are probably complex and our understanding of them incomplete, but they had applicability with regard to the rights of children to inherit their father's estate, the inheritance rights of the different types of "wife", the division of property and wealth following divorce, and the legal status of the woman (i.e. under whose rule she came, how much fine was payable if she was killed or raped, and how much fine was due and payable by whom if she committed a crime). 

In cases of rape, forced abduction, or where the woman did not consent to the sexual union, heavy fines were levied on the offender, and the responsibility for raising any child of the union fell on the offender and his kin. (8,11) This applied whether the woman was married, unmarried, a servant or a slave. (11)

Sex with servants was apparently commonplace, both heterosexual and homosexual. (8,14) The children of any such union may have become the father's responsibility, and may have adopted his surname, but this is unclear and would have depended on the circumstances and whether the mother had any rights.

In certain circumstances, the woman alone was responsible for rearing a child (presumably with the help of her own kin). These included if she was a prostitute, or if the father was a stranger / alien (cú glas), a slave, a satirist, a man expelled by his kin; a dependent son, who impregnated her without his father's permission; or a priest who later repented. What surname the child took in these circumstances is not clear, but no doubt in many instances a son would have retained the mother's surname, and in this way, the particular surname could have become associated with different Y-DNA.

Legal documents often consisted of large text (representing the original law) with explanatory text and interpretations in small print. The above is a detail from RIA MS 23 Q 6, p33.
From https://www.ria.ie/news/library-library-blog/brehon-law-manuscripts-reunited-galway-2020-european-capital-culture 

Divorce & Separation

Brehon Law allowed for women to divorce their husbands under specific circumstances, (8,11,13,14,15) including:

  • if he tricked her into marriage through sorcery
  • if he failed to support her
  • if he hit her and left a (permanent?) mark
  • if he insulted her in public
  • if he spread a false story or satire about her
  • if he discussed their sex life with others
  • if he became too fat to have sex
  • if he was impotent
  • if he preferred to lie with boys
  • if he rejected her for another woman
  • if he entered the priesthood
  • if he took a second "wife" without her knowledge (was this akin to our current concept of "infidelity"? Also, if he took a second wife/concubine with the knowledge of his first wife, would this then not be considered infidelity? In other words, you could do what you wanted as long as you told your spouse in advance??)
Men also had grounds for divorcing a wife including: 
  • "infidelity" (not further defined)
  • persistent thieving (... but occasional thieving was okay?)
  • bringing shame on her husband's honour
  • inducing an abortion
  • smothering a child
  • not being able to produce breast milk because of sickness

Furthermore women who left their husbands without just cause were stripped of their rights, denied shelter, and treated as outcasts. (8,11,14) There is no mention of this same treatment being inflicted on men, so the gender equality scales were not exactly balanced.

Another interesting example of grounds for divorce was if the couple were related by "affinity" i.e. if either party had had sex at any time in the past with a relation of their spouse, out to the level of third cousins. (13) Under Canon Law, the medieval church forbade marriage if the couple were 3rd cousins or closer, or if either had been married or had had sex (even once) with any of their prospective partner's relatives, out to the level of 3rd cousin. (How did they figure this out? Did they sit down and go through each other's family trees? Sounds like if you wanted to get married properly, you had to be a genealogist.)  If either party was previously married to a relative of the other (within the proscribed range), a papal dispensation would be necessary for the new marriage to be allowed and to be considered valid. Given society's relaxed attitude to sex, and the tendency to marry one's own kinfolk, it is likely that many marriages would not have been considered "valid"  in the eyes of the Church, but the couple managed to sail under the ecclesiastical radar ... or alternatively, could divorce each other at the drop of a hat. (12,13)

There were specific circumstances in which a couple could separate without being fined or penalised. Eleven such scenarios are listed in one book of Brehon Laws (Heptad 53) and these include death, entering the priesthood, and a variety of situations associated with temporary separation, such as going on a pilgrimage, searching for a far-off friend, going on a sea voyage, being in a revenge attack party, or being sick and requiring care away from home. But the most relevant situation with regard to Y-DNA is where the husband is infertile, the wife does not wish to divorce him, and instead goes away "to seek a child" by another man. The resultant child was treated as that of her husband - and in such a situation, the child would carry the husband's name but another man's Y-DNA. (11, p75)

Illegitimacy

Under Brehon Law, there was no concept of "illegitimacy" as we know it today  - every child was cared for by kin, no matter what their origins, be it a legal marriage, a casual fling, or an illicit tryst. In addition, there was apparently no social stigma, no concept of "the fallen woman" who had become pregnant "out of wedlock". Their attitude to such things was very different to that of (for example) 20th century Ireland. (8,11,13,14)

And these children, born outside of legal marriage, had equal rights to inherit their biological father's estate. (11,13) Just a few years ago (in 2022), legislation was passed by the Irish parliament that restored this prior right that such illegitimate children would have enjoyed under Brehon Law. The only thing that "out-of-wedlock" children were barred from doing was being a priest, apparently because "the child carried the sin of the mother".

In medieval Ireland, sometimes entertaining the guests went a lot further than just having them over for dinner. This is evidenced by the custom of "Naming" of children. In this case, a married woman, usually on her deathbed, would reveal that one of her sons had in fact been fathered by a man other than her husband, and usually quite a famous man with status, wealth and property. This newly illegitimized son thus became entitled to inherit the estate of his new father, but could also fall under his protection (thus securing his safety when his mother was no longer around to protect him). There are numerous contemporary examples of these "named children" and some of them (or their own children) became clan chiefs (e.g. in the latter half of the 1500s, James Meagh became chief of the O'More's, and Feardorcha O'Neill's son Hugh O'Neill became Earl of Tyrone). (13) Undoubtedly some of these "naming" events were pure lies, but this is another example of how different Y-DNA could become associated with a particular surname.

Adoption & Fosterage

Fosterage was very common in medieval Ireland. Parents would give a child for fosterage to another family if they wanted to forge strong links with that family, or if they wanted their child to learn a profession. The period of fosterage was usually up to to seventeen years old for boys, and up to 14 years old for girls (after which they became nuns or wives). (11)

If a child was adopted (by a childless couple, for example), it is likely that they would have carried the surname (but not the Y-DNA) of the adoptive father. But if a child was fostered, then they probably retained the surname (and Y-DNA) of their biological father. The only circumstance where the fostered child might adopt the name of the foster father, might have been if the natural father died while the child was being fostered.

The Election Process

The way clan chiefs were elected changed considerably over time. The Irish clans operated under Brehon Law and the system of Tanistry, whereby a successor for the chieftainship would be chosen from relatives within the derbfine, i.e. direct male line relatives of the chief out as far as "the fifth degree of relationship" (roughly second cousins). (13) As a result, the Y-DNA signature of the clan chief should have remained relatively unchanged down through the generations, because subsequent clan chiefs would be related to him on his direct male line. However, it is possible that the DNA of the Clan Chief may have varied from time to time, if a DNA switch had occurred on the direct male lines of relatives within the derbfine. And thus (for example), the various genetic groups with Mayo origins that we see in the O'Malley DNA project today, may have been associated (at one time or another) with an O'Malley chief that carried their DNA signature. 

This Irish system of Tanistry was eventually replaced when the English system of primogeniture was foisted upon the clans (including the O'Malley's) following the Composition of Connaught in 1585. (16,17) Thereafter, the role of chief should have been passed from father to eldest son (the law was not always obeyed), thus probably reducing the opportunity for different DNA signatures to be associated with the role of clan chief.

Summary

So, to recap, the potential medieval causes for different genetic signatures being associated with the same surname may have included the following ...

  1. multiple origins for the same surname
  2. anglicisation of Irish surnames to English approximations
  3. switching surname as an act of fealty / loyalty ("surname gravity")
  4. having your surname switched as an honour / distinction bestowed by a clan
  5. changing your surname to that of your higher status wife
  6. being the child of failed trial marriage (and taking the mother's surname)
  7. the child being raised by the mother on her own (and taking the mother's surname)
  8. the wife being impregnated by another man if her husband was infertile
  9. a child in fosterage adopting the name of the foster father following the death of his biological father
  10. being a "named child"(i.e. the result of a union with a man of high status)

Maurice Gleeson
May 2024

An earlier version of this article appears on the O'Malley DNA Project blog here.

Sources & Links

1) History of the Law in Ireland. Available at the website of The Courts Service of Ireland.

2) Woulfe, Patrick. Sloinnte Gaedheal is Gall: Irish Names and Surnames, collected and edited with explanatory and historical notes (1923). Available at https://www.libraryireland.com/names/contents.php

3) Westropp, T.J. (1916) The antiquities of Limerick and its neighbourhood. Dublin: Hodges Figgis & Co. Available from the Archive.org website here. Note that pages 81 and 140 are missing from this version but can be found in this alternative version on the AskAboutIreland website here.

4) Murphy, P. The Anglicization of Ireland: A Model for the Linguistic Imperialist? Available online here.

5) Crowley, AE (2016) Language, Politics and Identity in Ireland: a Historical Overview. In: Hickey, R, (ed.) Sociolinguistics in Ireland. Palgrave Macmillan , London , pp. 198-217. ISBN 978-1-137-45347-1

6) Clan FAQs at https://www.scotclans.com/pages/clan-faqs

7) Chambers, A (2009, 7th edition). Grace O'Malley: The Biography of Ireland's Pirate Queen 1530–1603. Gill Books. Available from http://www.graceomalley.com/

8) Kerrigan, J (2020) Brehon Laws: The Ancient Wisdom of Ireland. Free Kindle edition available here.

9) Castlelow, E. Oliver Cromwell. Biographical article at Historic UK website available here.

10) Trowbridge, B (2016) Meeting Grace O’Malley, Ireland’s pirate queen. This article includes digital images of Grace's petition to Queen Elizabeth I (Catalogue reference: SP 63/170 f. 204) as well as the 18 "interrogatories" and her responses (SP 63/170 f. 201-202). Available at The National Archives blog.

11) Kelly, F (1988, reprinted 2016) A Guide to Early Irish Law. School of Celtic Studies, Dublin Institute of Advanced Studies. Available from DIAS here.
Prof Fergus Kelly is a Senior Professor in the School of Celtic Studies at the Dublin Institute for Advanced Studies (DIAS).

12) Simms, K (1975) The Legal Position of Irishwomen in the Later Middle Ages. Irish Jurist, vol.10, pp96-111. Available to read or download here.
Katharine Simms is Senior Lecturer in Medieval History in the School of Histories and Humanities, Trinity College Dublin.

13) Nicholls, K. (2003, 2012 digital reprint) Gaelic and Gaelicised Ireland in the Middle Ages. The Lilliput Press. Kindle Edition available from Amazon here. 
Kenneth Nicholls is a former Professor of History at University College Cork.

14) Duggan, C (2013) The Lost Laws of Ireland. Glasnevin Publishing. Kindle Edition. Paperback edition available here.

15) Ginnell, L (1898, reprinted 2011) The Brehon Laws: a Legal Handbook. Read Books Ltd.. Kindle Edition available from Amazon here. Also, freely available from the LibraryIreland website here.
Laurence Ginnell (1852-1923) was an Irish nationalist politician, lawyer and Member of Parliament (MP).

16) Cunningham, B (1984) The Composition of Connacht in the Lordships of Clanricard and Thomond, 1577-1641. Irish Historical Studies, Vol. 24, No. 93 (May 1984), pp. 1-14. Available online here.

17) McInerney, L (2011) The Composition of Connacht: an ancillary document from Lambeth Palace. North Munster Antiquarian Journal vol. 51. Available online here.



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Friday, 3 November 2023

Making the most of your Y-DNA Results

Why have you done an expensive Y-DNA test? Presumably to help you with your family tree research, and specifically the ancestral line down which your surname passed, generation after generation, since the formation of your surname, perhaps some 800-1000 years ago.

So it makes sense to share the results of your Y-DNA test with the right people in order to maximise your chances of making a breakthrough on your direct male line (father father father etc). That way you are getting value for the money you spent on the test in the first place. 

However, at the same time, you want to make sure that you protect any sensitive personal information. You do not want any information made available to the general public that identifies you as an individual - you want to focus primarily on reaching those like-minded people who are also researching their surname. And by finding them and collaborating with them, a breakthrough is possible.

This article shows you what information is published on the public Results Pages of DNA Projects you have joined at FTDNA (FamilyTreeDNA) so that you can decide whether you want to 1) make your results public (and maximise your chances of a breakthrough) or 2) keep them hidden (so that your privacy is optimised).

First of all, this is what your Y-DNA results would look like if you chose to have them published on the public Results Page of any project you might happen to join at FTDNA. Note the following:

  1. the row number does not identify you as an individual
  2. your Kit Number does not identify you as an individual
  3. your "Name" (i.e. surname or family name) does not identify you as an individual (unless you are the only person alive with that particular surname)
  4. your "Paternal Ancestor Name" does not identify you as an individual (unless you are the sole surviving descendant of that particular ancestor)
  5. the Country of origin does not identify you as an individual
  6. the Haplogroup does not identify you as an individual
  7. the numerical values for each individual STR marker do not identify you as an individual

Typical display of Y-DNA results on the public Results Page of a DNA Project 
(click to enlarge)

So there is no data displayed that clearly identifies you as an individual. And if you are happy with that, then you should consider making your data available for other researchers to see.

One of my own particular interests is Irish Clan research and making your data available on the public Results Page allows researchers like myself to use the data in our Irish Clan research as well as individual surname research, which ultimately benefits you and your family and all your relations associated with your surname line.

Here is how you make your Y-DNA results publicly-viewable ...

1) log in to your account at FTDNA

2) go to Account Settings (from the drop down menu when you click on your name in the top right)

3) click on the Project Preferences tab

4) scroll down to Project Sharing

5) click on the "Opt in to Sharing" button, so that it turns from grey (OFF) to dark blue (ON)


And that's it. Your Y-DNA results will be visible on the public Results Page of any projects you have joined at FTDNA. And you can reverse your decision at any time you want. Just click on the same button and it turns itself OFF. Simple!

Now your Y-DNA results are working for you in the background rather than being hidden away doing nothing.

Maurice Gleeson
Nov 2023




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Wednesday, 8 December 2021

Unexpected Y-DNA results - as an Admin, what do you tell the test-taker?

Someone does a Y-DNA test to find out more about their direct male line and "where my surname came from" only to find that the results are not what they expected. So they join the DNA project relevant for their surname and ask the Administrator for an interpretation. What information are they going to find useful? And, as an Admin, what information can you give them?

These were the questions I pondered recently when a new project member joined my O'Malley DNA Project. And I think it would be useful to take you through my response to his email and point out some of the challenges that Admins face when confronted by the unexpected results of one of their project members.

I have privatised any identifying information. My comments are in italics.


Dear Mr O'Malley

I had a look at your results and here are some top line observations …

You have 13 matches at the 111-marker level of comparison, 20 matches at 67 markers, and 20 at 37.
Your top matches are to people called Leyden/Layden/Lyden, Ward & Corcoran.
You have no O’Malley’s among these matches.
You do not match any of the genetic groups within the O'Malley Project.

This suggests that there may have been a Surname or DNA Switch somewhere along your direct male line, which means that your Y-DNA signature was associated with some other surname prior to switching to O’Malley. This could have happened relatively recently, or centuries ago. The previous surname could have been Leyden/Layden/Lyden, Ward, Corcoran ... or some other surname.

Already we may have shattered a lot of the hopes that the test-taker may have had when they first took the Y-DNA test. Some people may be interested in the deeper origins of their surname, but I suspect that the reason most of us do any type of DNA test is to help with our genealogy and perhaps to break down a specific Brick Wall. In the case of Y-DNA, the Brick Wall will be on the direct male line, and in the case of Irish genealogy, this typically halts abruptly at 1800. So, for many test-takers (including perhaps Mr O'Malley above), the hope with Y-DNA may be "can it help me break through my 1800 Brick Wall and push it back by a generation or two into the 1700s?". Alternatively, the Brick Wall may be more recent (say mid-1800s) and the test-taker's genealogy may be stuck in America (for example), in which case the hope may be "can Y-DNA help me jump back across the pond to Ireland?". Another possibility is that the test-taker has explored the relevant surname project and sees that there are several well-defined genetic groups within the project and wants to find out which one of these he belongs to.

In all of the above cases, Mr O'Malley will be disappointed. He was aiming to find an O'Malley in Ireland, and instead he has discovered that he is "not an O'Malley". Has his line of genealogical enquiry been completely derailed? Is his Y-DNA telling him he is not on the right track? Has he been sidelined into completely foreign territory?

As an Admin, what do you do in such a situation? What kind of information might be helpful for the test-taker? What information can help him navigate through this new uncharted territory?

The sort of additional questions that may arise include: 
  • if I am not an O'Malley, what am I? what surname did my ancestors carry before it was switched?
  • where did the name come from?
  • when did the switch happen?
  • why did the switch happen? was there some secret adoption or illegitimacy in the recent past? or did the switch happen centuries ago, for reasons lost in the mists of time?
  • do I have any hope of breaking through my Brick Wall? and what's on the other side - is it an O'Malley or a complete stranger?

The sad truth is that Y-DNA is severely limited in its ability to answer these questions. It will possibly give you some clues, but the answer may not be definitive and you may have to spend a lot of money on expensive tests to arrive at a nebulous conclusion. I know this sounds pessimistic ... but that's because it is. From the perspective of day-to-day genealogy, there is a lot less to Y-DNA than meets the eye ... especially when you compare it to the information you derive from autosomal DNA testing. I'm not saying its useless ... just less useful, from a genealogical point of view. And I feel as frustrated about this as the average test-taker.

Update: some feedback on this post spurs me to make some additional points:
1) another possibility is that this man comes from a very rare branch of O'Malley's - a branch that arose completely independently of the other major branches and is in no way connected to them in the immediate pre-surname era (e.g. 700-900 AD in Ireland) - and he is currently the only man from this rare branch in the entire FTDNA database. He will have to wait for another member of this rare branch to join the project before he (and this new member) can be allocated together to a new genetic subgroup. I sometimes mention this in feedback to new members with an SDS / NPE but the O'Malley DNA Project is quite mature and a variety of genetic subgroups have already been identified, and there are no outstanding O'Malley groups mentioned in the historical record (e.g. surname dictionaries) so I would be very surprised if any additional rare subgroups were to emerge (it is not impossible but it is improbable) - hence I decided not to mention this rare possibility in this particular reply. I may mention it if the response from the project member raises any questions about the probable SDS, but it is always a balance between giving just enough information to adequately inform the new member and not too much that it overwhelms the recipient. It's a judgement call. What would you have done? Hmmm ...
2) Most people take the prospect of an ancestral surname switch quite well, but some jump to the decision that they have wasted decades of research on their genealogy and half of it is now useless. I go to pains in my presentations to explain how commonplace such SDS / NPE events are and point out that each of us has somewhere between a 33% to 55% chance that our direct male line does NOT go back to the progenitor of the surname that we carry today. So if we insisted that you could only call yourself an O'Malley if you matched the DNA of the progenitor of the surname, then about half of us would not be who we thought we were. For me, anyone who carries a surname, owns that surname, and has every right to claim that surname's history and heritage - "an O'Malley by any other name would smell as sweet".

Here's how I continued my response to my new project member. I veered into deeper origin territory and if you get the impression that I was clutching at straws, you may be right ...

Your matches are relatively distant. The closest matches have a Genetic Distance to you of 6 at the 111-marker level of comparison (i.e. 6 steps away from an exact match), 3 out of 67, and 3/37. Nevertheless, it may be helpful to write to each of them and ask if they have any connection to the O'Malley surname. The geographic origin of their MDKA (Most Distant Known Ancestor) may also provide some clues.

We could get further clues from looking at SNP markers. Some of your matches have done SNP testing (usually the Big Y test) which allows us to see where they sit on the Tree of Mankind. The question is - is there a pattern? Here are the SNP Sequences (i.e. list of ancestral SNP markers) for your matches at 111 markers (generated via the SNP to Breadcrumbs tool here):
  • R-L21 > S552 > DF13 > DF21 > S5488 > Z16294 > BY4001 > L130 > BY3308 > BY16783 > BY16785
  • R-L21 > S552 > DF13 > FGC11134 > FGC12055 > Z3026 > Z16250 > A114 > CTS4466
  • R-L21 > S552 > DF13 > DF21 > S5488 > Z16294 > BY4001 > L130 > BY3308 > BY16783 > BY16787 (x2)
  • R-L21 > S552 > DF13 > DF21 > S5488 > Z16294 > BY4001 > L130 > BY3308 > BY16783 > BY16785
  • R-L21 > S552 > DF13 > DF21 > S5488 > Z16294 > BY4001 > L130 > BY3308 > BY16783 > BY16787 > BY16790 (x2)
  • R-L21 > S552 > DF13 > DF21 > S5488 > Z16294 > BY4001 > L130
  • R-L21 > S552 > DF13 > DF21 > S5488 > Z16294 > BY4001 > L130 > BY3308 > BY16783

From the above we can see that most of your SNP-tested 111-marker matches fall on or below the branch characterised by the SNP marker BY16783 (in bold). It is therefore likely that (if you were to do SNP testing) this is where you would sit too.

You can see the path of migration of the people who sit on this particular branch of the Tree here … http://scaledinnovation.com/gg/snpTracker.html?snp=R-BY16783.



This SNP marker arose about 2400 years ago (i.e. 400 BC, well before the advent of surnames), probably in Ireland.

Rob Spencer's tools are great for illustrating the deeper origins of a particular SNP marker and the SNP Tracker tool provides a great visual that captures the imagination. Customers like it. However, this is closer to archaeology than genealogy, and does not address the immediate questions of the test-taker as described above ... but is it the best we have to offer?

Only 7 people fall on or below this branch (according to FTDNA's public Y-DNA Haplotree) - 2 report Ireland as their ancestral homeland, 1 reports USA.



The Big Y Block Tree (which is visible only to those who have done the Big Y test) shows the more fine-detailed branching structure of this portion of the Tree of Mankind, including the number of SNPs associated with each branch.



It is a pity that the Big Y Block Tree is not publicly viewable, unlike Alex Williamson's "Big Tree" which has proved to be so useful over the years. Nowadays the Block Tree has much more data than the Big Tree and better delineates the more fine-detailed branching structure of the Tree of Mankind. However, a big drawback of the Big Y Block Tree is that it does not display surnames for each and every branch. I wish it would. Instead it reports the entire name for matches (rather than just the surname) and only for those matches closest to the test-taker in question. This makes it far less useful as a research tool. We don't need to see the entire name of matches on the Block Tree - just the surname would do very well thank you.

The next question is - what surnames do we find most commonly in this portion of the Tree of Mankind?

We already know that common surnames among your matches are Leyden/Layden/Lyden, Ward & Corcoran. We can look at relevant Haplogroup Projects to see if there are any others. And the relevant Haplogroup Projects for this portion of the Tree includes the R-DF21 and subclades project (1664 members). This has the following people grouped under or near BY16783 …


From this we can see that the surname Duffy sits on a neighbouring branch.

It is unfortunate that new members are not added automatically to the Haplogroup Projects relevant to their Y-DNA signature. This would help make Y-DNA testing more useful to FTDNA's customers. In the present case, only a handful of relevant matches have joined the project and this decreases the value of the Haplogroup Project for research purposes.


Is there a pattern for the distribution of these surnames on Surname Distribution Maps?



It is difficult to draw any firm conclusions from this, but there may be a preponderance of these various surnames in the west of Ireland, around Galway & Mayo, and this suggests that this could be where this particular SNP marker arose. Coincidentally, this is close to the origins of the Mayo O'Malley's.

You may benefit from joining the R-DF21 and subclades project - the Admins there could offer additional insights into the origins of your Y-DNA signature. 

There are no DNA Projects for the surnames Corcoran, Duffy or Leyden/Layden/Lyden, otherwise I would have referred him there too. There are a few Leyden's and Layden's in the Lyddon/Lydon/Liddon Project so that might be worth joining, but none of the participants on the public Results Page sit anywhere close to BY16783.

For now, I have moved you into the Ungrouped section of the O'Malley project. This will change if another O’Malley tests and joins the project and is a match to you.

Hope you find this of interest.

Best, Maurice


So there we have it. Have we been able to answer any of the burning questions this test-taker may have had? Let's recap on what they might have been ...
  • if I am not an O'Malley, what am I? what surname did my ancestors carry before it was switched? 
    • we are still none the wiser - our additional analysis has not pinned down a most likely candidate
  • where did the name come from?
    • possibly the west of Ireland.
  • when did the switch happen?
    • we still have no clue. Only (expensive) sequential Y-DNA testing of progressively more distant male cousins could possibly address this question (but only if it was within the last 200 years or so). See an example here from the Gleason DNA Project.
  • why did the switch happen? was there some secret adoption or illegitimacy in the recent past? or did the switch happen centuries ago, for reasons lost in the mists of time?
    • we may never know the answer to this question. If it was a recent switch, there may be some clues in documentary records (e.g. the lodger's name was Corcoran and he lived with the family for 20 years after the husband left).
  • do I have any hope of breaking through my Brick Wall? and what's on the other side - is it an O'Malley or a complete stranger?
    • his close matches may offer some clues.
    • Big Y testing may place him on a specific branch of the Tree of Mankind that is associated with a specific single surname, but with only 7 people sitting on or below BY16783, it may be that a specific single surname cannot be identified and therefore no firm conclusions can be drawn. In which case it is a waiting game for more people to join the databases and do the Big Y test and fall on the same or adjacent branches.
    • autosomal DNA testing may help if the Surname or DNA Switch has been recent (i.e. within the last 200 years).

So the test-taker has been supplied with a huge amount of information to digest ... but at the end of it all, he still remains in limbo. He does not match any of the O'Malley groups within the project. His closest matches are not that close and have completely foreign surnames. He arrived with a whole list of questions and leaves with a whole set of new ones (and the original list unanswered). His options for moving forward are limited and his Brick Wall looms larger than ever.

This unfortunately is the current state of the art.

Maurice Gleeson
Dec 2021






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