Interpreting the Results

The interpretation of Y-DNA results is a 2-step process. The first part involves grouping project members together who share similar genetic signatures. The similarity of the signatures suggests that these people are related within a genealogical timeframe (i.e. since the formation of surnames, which roughly equates with the last 1000 years when we are considering Irish surnames).

Having successfully allocated people to various genetically similar groups, the second step in the process involves analysing the groups and addressing a series of questions in relation to each group. These questions can include:

1. Where is the group from? 
2. Where did the name arise?
3. Where do they sit on the Tree of Mankind?
4. Who are their nearest genetic neighbours?
5. Does this give any clues to their origin?
6. Does this fit with the history of the surname?
7. How long have they carried the surname?
8. Is there any evidence of a Surname or DNA Switch (SDS)?
9. Is there any evidence of Chance Matches?
10. What is the branching structure within their group?
11. When was each branch formed?

Grouping people together

The members of this project are divided into groups on the basis of their Y-DNA & genealogical data. This used to happen automatically overnight at the WFN website* but since this closed down in 2018 due to GDPR, this process is now done manually.

Each new member has a list of people who "match" them. These Y-STR matches are people whose Y-DNA signature appears to be relatively close to that of the new member. The criteria for people being declared "a match" and being included on the match list is based on Genetic Distance (GD) i.e. the number of steps away from being an exact match. Thus a GD of 0 is an exact match (no differences in the values for the STR markers between the two people) whereas a GD of 3 indicates the two Y-STR signatures being compared are 3 steps away from an exact match to each other.

The thresholds used by FTDNA for declaring a match are as follows: <2/25, <4/37, <7/67, <10/111 

However, not all matches meeting these criteria should be grouped together. Some may be "chance matches" (due to Convergence) and so other criteria for grouping need to be applied. I call these Markers of Potential Relatedness (MPRs) and they include the following key criteria. The people being compared have ...

• the same surname (or variant thereof)
• the same MDKA birth location (e.g. their ancestors came from same county in Ireland)
• the same (or compatible) terminal SNP marker
• the same Unique STR Pattern
• the same Rare Marker Value

I gave a presentation on grouping at the FTDNA Annual Conference 2017 and you can see it here. It goes into a lot more detail regarding the process of grouping.

Analysing the Groups

In order to address the questions identified in the opening paragraph above, a variety of analytical techniques can be used to try to collect evidence that may point towards a particular answer. Let's take each of the questions in turn and look at how we might address them:

1. Where is the group from? 
2. Where did the name arise?
3. Where do they sit on the Tree of Mankind?
4. Who are their nearest genetic neighbours?
5. Does this give any clues to their origin?
6. Does this fit with the history of the surname?
7. How long have they carried the surname?
8. Is there any evidence of a Surname or DNA Switch (SDS)?
9. Is there any evidence of Chance Matches?
10. What is the branching structure within their group?
11. When was each branch formed?

1. Where is the group from?
2. Where did the name arise?
In order to answer either or both of these related questions, it is essential that MDKA information is provided by all project members. Without the birth location of the MDKA (Most Distant Known Ancestor) it becomes very difficult to determine with any degree of certainty where a particular group is from. Furthermore, "Old World" pedigrees are essential if the leap is to be made from the "New World" (e.g. US, Canada, Australia) back across the ocean to the "Old World" (e.g. Ireland, England, etc).

There are other techniques and sources of information that can potentially help address these questions but the outcome from these techniques is rarely definitive. These include:

• Surname dictionaries
• Surname distribution maps
• Nearest Neighbour Analysis using SNP data

These techniques will be explored in subsequent blog posts relating to each of the groups.

3. Where do they sit on the Tree of Mankind?
4. Who are their nearest genetic neighbours?
5. Does this give any clues to their origin?
6. Does this fit with the history of the surname?
SNP data provided by the Big Y test or SNP Packs can help place people accurately on the Tree of Mankind. This Human Evolutionary Tree shows not only on which branch a particular group sits, but also who is sitting beside them. And this information may tie in nicely with historical data from ancient texts (e.g. the Ancient Irish Annals & traditional genealogies) which can lend support to a theory of a particular origin for a group.

7. How long have they carried the surname?

This is a very difficult question to answer. There are tools and techniques available for calculating the TMRCA (Time to Most Recent Common Ancestor) for the entire group as well as the various branching points on the Tree of Mankind within the last 1000 years, but these are crude and the output is inexact. These time estimates usually carry broad ranges on either side of them (usually 200-400 years ... on either side). So although they are statistically accurate, they are genealogically inexact and are not exactly what we would call "fit for purpose". Nevertheless, we are stuck with them because there is nothing better. It is the nature of the beast, unfortunately.

Tools that can be used to calculate how long a particular group has been carrying the surname in question include the following:

• good old-fashioned pedigrees 
• FTDNA's TiP Report (very crude indeed)
• dating using SNPs (e.g. YFULL's methodology)
• dating using SNPs, STRs & genealogies (e.g. Dave Vance's SAPP Programme, which incorporates Ken Nordvedt's Interclade Ageing methodology)

8. Is there any evidence of a Surname or DNA Switch (SDS)?

Each of us has roughly a 50:50 chance that our surname goes back to the person who originated it (some 1000 years ago or thereabouts). And for the other half of us, there will have been a switch in either the surname or the DNA somewhere back along our father's father's father's line. For some it may hundreds of years ago; for others, it may be only one generation back!

There are a variety of different causes for an SDS (also known as NPEs, or Non-Paternity Events, or Not the Parent Expected). Some of the time it will be due to a secret adoption, or an illegitimacy, and at other times it may be due to nothing more innocent than a young widow remarrying and her children (by her first husband) taking the name of her second one.

And this is one of the reasons why people with surnames different to the one in question appear within some of the groups within the project. For example in R1b-Lineage I there are several Kennedy's, a Foley, a Dwyer, a Butler, and a Leonard. Has there been an SDS somewhere along their direct male line? Are they Kennedy's by name but Ryan's by DNA? Or is it the other way around? This type of "chicken and egg" scenario requires some careful analysis in order to distinguish between the two options.

9. Is there any evidence of Chance Matches?

These arise due to a technical phenomenon that occurs when two or more genetic signatures mutate in such a way that over time they grow more similar to each other (as opposed to more different). They begin to approximate each other. And this can reach the stage where they may even be declared as "matches" to each other (using FTDNA's criteria for matching). Thus, two people who may appear to share a common ancestor within the last few hundred years may in fact be related thousands of years ago. 

This phenomenon is known as Convergence and each group needs to be assessed for the likelihood that it is present to a significant degree - if it is present, this can be very misleading and incorrect conclusions can be drawn.

10. What is the branching structure within their group?

11. When was each branch formed?

Once enough people are present in a group  it is possible to generate a "genetic family tree" for the group based on the DNA markers rather than the named ancestors. This uses phylogenetic programmes such as Dave Vance's SAPP Programme, which has been especially designed for use in genealogy.

Knowing the branching structure gives us a better feel for the evolution of a particular group over time. In addition, estimating the dates for each branching point can give us useful information about when one branch of the surname split away from another branch and can point to migration events (either within Ireland or outside of it). 

These trees rely on mutations within the DNA markers to build a "best fit" model of how the tree evolved over time, and therefore they are often called Mutation History Trees (i.e. akin to Family History Trees ... except they use mutations instead of ancestors).


Addressing the above questions will provide many answers relating to the nature of the groups in the project. This will also generate more questions that will require further research. It is hoped that over time we will be able to shed some light on the various groups of people who carry the Ryan surname today, where it came from, and how long each group has carried it.

Maurice Gleeson

March 2018

* Hopefully automatic grouping will be re-introduced by FTDNA at some stage. Currently anyone can do this by entering any project's Results Page web address (i.e. URL) into Chase Ashley's Y-DNA Family Grouping app.

The process at WFN (World Families Network) was as follows:

Each new member had their genetic profile compared against each genetic profile of every other member in the project, or against the Apparent Ancestral Profile (i.e. group modal haplotype) of any established groups within the project (i.e. the Lineages). The new member was grouped with other members if the genetic distance between them was:

• Definite ... <2/25, <4/37, <7/67, <10/111 
• Possible ... 3/25, 5/37, 8-9/67, or about 11-13/111

These criteria would successfully allocate about 90% of project members to the correct group. Anyone not allocated would be put in the ungrouped sections (i.e. "No Match Yet in the Project"). These people would be manually reviewed by the Admin and assessed for "Markers of Potential Relatedness" (e.g. SNP markers) to determine if they should in fact belong in one of the established groups.  In this way, any outliers missed by the automated grouping process would (hopefully) be captured during manual review.