Friday, 23 September 2016

The Origins of R1b-GF5

(Please note: for added security, project members are now described by their initials and the last 4 digits of their kit numbers)

The results of a new participant (GTJF-6791) have recently become available and he most closely matches the members of group R1b-GF5. So this presents a nice opportunity to review the characteristics of this group.

The new member has a Genetic Distance of between 2/37 and 6/37 to other members of the R1b-GF5 group. He also matches an Ungrouped Farrell project participant (SF-0861), which raises the possibility that this person could also belong to R1b-GF5. We'll look at that possibility later.

Ancestral Locations for R1b-GF5
There are currently 7 members in R1b-GF5. Surname variants include Farrelly (x3) and Farley (x3). There is also a member called Walsh which may be an NPE or an example of Convergence.

MDKA locations for these members include counties Leitrim (x1) and Meath (x1) in Ireland, and Illinois (x1) in the US. Five of the 7 members have listed Ireland as their country of origin. It would be helpful if all members could list birth locations for their MDKA (Most Distant Known Ancestor). See how to do this here.

R1b-GF5 on the Results Page of the Farrell DNA Project website

The Nearest Neighbours to R1b-GF5
Three members have tested to 37 markers, 2 to 67 markers, and 2 to 111 markers. Among their matches, the surnames Beatty, Berry and Byrne turn up frequently, suggesting that there may have been a surname or DNA switch with these families at some time in the past. But which came first? Did Beatty become Farrelly? or did Farrelly become Beatty? The same considerations apply to Berry and Byrne/Burns. The distribution of the surname Beatty in particular has an overlap with one of the traditional ancestral origins of the Farrell surname (i.e. the midlands / Longford).

Mid-1800 Surname Distribution maps of Nearest Neighbours of R1b-GF5

An alternative explanation is that these matches are the result of Convergence (i.e. chance matching).  This is suggested by the fact that three of the members who have tested to at least 67 markers, have more than 100 matches at this particular level of comparison. Further DNA testing (with the Z255 SNP Pack - see below) would help resolve this question.

Which branch of the Human Evolutionary Tree is it on?
On examination of the terminal SNPs of the matches among R1b-GF5 members, there is again evidence of Convergence with several different downstream SNPs occurring (e.g. FGC32916 > A1154 > BY3247, A1235, Z16432, Z16434, and Z16950 ... all adjacent downstream branches). However, all of these adjacent branches fall below Z255 so it is very probable that all R1b-GF5 members will test positive for Z255, and it is recommended that one of them at least orders the Z255 SNP Pack.

Close neighbours to R1b-GF5?

Rare Marker Values
In terms of rare marker values, the modal value for marker CDYa is 39 and this occurs in only 4% of the R1b population. Other than that, there is no evidence of rare marker values.

Other possible members from the Ungrouped section
Finally, review of the Genetic Distance between R1b-GF5 members and all other participants in the Farrell DNA Project suggests that there may be one other person who is currently Ungrouped who may belong to R1b-GF5. This is the project member SF-0861 mentioned in the second paragraph above. At the 111 and 67 marker levels, R1b-GF5 members only match other R1b-GF5 members. But at the 37-marker level of comparison, SF-0861 comes up as a match to three R1b-GF5 members, with a GD of 7/37 each time. So for the time being I have placed him in this group. The accuracy of his membership of R1b-GF5 could be confirmed by doing the Z255 SNP Pack.

Next Steps
  1. Full MDKA information should be included for all group members. The most important information is the surname and the birth location of the MDKA (Most Distant Known Ancestor). See how to do this here.
  2. The Z255 SNP Pack is recommended for members of this group. Ideally, at least 1 or 2 members should do this test. The tentative member SF-0861 should definitely do this test, in order to confirm that he does indeed belong to this group.
  3. Ideally, 1 other person within the group should do the Big Y test ($575), but I'd recommend waiting until the next FTDNA sale when it may come down in value to about $460.
  4. All members are reminded to follow the suggestions in the link below in order to maximise the benefit from their DNA results ... Getting the Most out of your DNA Test

No comments:

Post a Comment