Two years ago, I looked at whether Y-DNA genetic distance was an adequate predictor of relationships. Using a number of participants at both 37 and 43 markers, I concluded that genetic distance was an insufficient predictor of relationship range. This post examines the following question: “Would an STR marker test at 111 markers enhance the ability to predict relationships?”
In the past two years, the Owston/Ouston DNA project has had the opportunity to upgrade fifteen men to 111 markers. At this resolution, our 15 project members only have matches within our surname group, which indicates it is a sufficient tool to narrow the results to a particular family group. By comparison, each of us matched several men with a number of surnames at 67 markers. At 37 markers, we matched nearly 400 men with different surnames. We can testify that the 111 test has been sufficient enough to separate the wheat from the chaff in our one-name project.
Our 15 subjects represent three families of a low-frequency surname group that totals an estimated 296 males. These 296 men and boys, yes I counted them, have residence in the UK, the USA, Australia, Canada, New Zealand, Finland, and France. Testing subjects represent all the aforementioned countries except France; however, the son of the lone Frenchman, who lives in England, has tested. A brief synopsis on these families is found below.
SHERBURN FAMILYA total of 19 men from the Sherburn family have tested: six exhibited ancestral non-paternity events, two remain to be upgraded from 43 markers, and 11 have been tested at 111 markers. Of those 11 subjects, the relationships range from siblings to 11th cousins, once removed. The Sherburn family’s most recent common ancestor was alive in the 1550s and died in 1602. Seventy percent of all Owston/Ouston males descend from this family. The most distant relationship within the family is that of 13th cousins.
The Sherburn family includes the Cobourg line that is well represented in the project with seven participants – six at the 111 level. The Cobourg line shares a most recent common ancestor who lived between 1778 and 1857. The most distant relationship represented in this project is that of fourth cousins, once removed. The most distant relationship among all males of this line is at the sixth cousin level. A total of 22 Owston and non-Owston relatives in the Cobourg line have also participated in autosomal testing. This is the author’s line and the reason for its over representation – convenience sampling.
GANTON FAMILYA total of four men from the Ganton family have tested: two were tested at 43 markers, but died before upgrading at FTNDA. The remaining two, who have tested at 111 markers, are fifth cousins. The family’s most recent common ancestor lived from 1753 to 1823 making the family’s most distant relationship that of seventh cousins. The Ganton family represents 21% of living Owston males.
THORNHOLME FAMILYA total of five men from the Thornholme family have tested and all four extant lines are represented. Two men exhibited ancestral non-paternity events, one has not yet upgraded from 43 markers, and the remaining two have tested at 111 markers. These two individuals are seventh cousins once removed.
The family’s most recent common ancestor died in 1739 and was probably born in the 1670s. Being the smallest of the three families, the Thornholme family has only 25 males, which constitutes 9% of the total number of Owston/Ouston males. The most distant relationship found within the Thornholme family is that of 9th cousins.
INTERFAMILY RELATIONSHIPSData for this one-name study comes from the individual and combined research of Timothy J. Owston, Roger J. Ouston, and James M. Owston. While each began researching the surname in the 1970s, their combined efforts began in 1990 when they crossed research paths.
As noted, a total of 15 men have tested at 111 markers; this represents 105 relationships. While intrafamily relationships are easily tracked, the difficulty arises in cross-family relationships, as records prior to 1550 are spotty. Matching Y-DNA has confirmed that the three families are related and they are from the same region; however, documentation on connections among the three families does not appear to exist.
To address the interfamily relationship problem, I have created a plausible tree based on naming conventions from the three current families and two extinct families who have originated in the Vale of Pickering that spans the historic border of the former North and East Ridings of Yorkshire. The first reference of the surname in this region appeared in 1452. I am confident that the relationships of these lines are within two generations (further distant) than I’ve charted. For this analysis, I used the closest possible relationship that could be presumed.
RELATIONSHIPSThe following charts and table enumerate the known (and assumed) relationships in this family.
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|2nd Cousins, Once Removed||1|
|4th Cousins, Once Removed||3|
|7th Cousins, Once Removed||1|
|8th Cousins, Once Removed||8|
|8th Cousins, Twice Removed||2|
|9th Cousins, Once Removed||7|
|9th Cousins, Thrice Removed||1|
|10th Cousins, Twice Removed||7|
|11th Cousins, Once Removed||2|
|12th Cousins, Once Removed||8|
|12th Cousins, Twice Removed||6|
|12th Cousins, Thrice Removed||1|
|13th Cousins, Once Removed||16|
|13th Cousins, Twice Removed||1|
|14th Cousins, Once Removed||2|
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RESULTSBy comparing the results of 15 subjects at 111 markers and the additional five participants at 43 markers, a modal haplotype has been constructed. Three participants shared the modal signature at 111 markers: Ganton03, Ganton04, and Cobourg08. The late Ganton01 also exhibited the modal haplotype at 43 markers. Several others who shared the modal haplotype at 37 and 43 markers did not at 111 markers.
There was a noted convergence with Cobourg08 who had a back mutation on DYS643 to 12 repeats, which was found in the modal haplotype. All of the other matching Cobourg line members have an 11 at this marker. This back mutation attributed to some of the outlying results in this analysis. The genetic distance (GD) for the 105 relationships at a 111 marker resolution ranges from 0-9. A GD of 2, however, was not recorded for any of the relationships.
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The following table delineates the generational range, mean, the adjusted mean relationship, and the standard deviation for the results.
|1||5||15||11.46||10th Cousins, Once Removed||4.68|
|3||3||15.5||10.60||9th Cousins, Once Removed||4.88|
|4||5||14.5||12.48||11th Cousins, Once Removed||2.34|
|5||5.5||14.5||11.68||10th Cousins, Once Removed||2.71|
|6||9||15||10.53||9th Cousins, Once Removed||1.99|
|7||9.5||15.5||12.50||11th Cousins, Once Removed||2.17|
|9||9.5||13||10.38||9th Cousins, Once Removed||1.80|
Outside of a GD=0, the adjusted mean relationship for genetic distances of 1 to 9 ranges from ninth cousins, once removed to 12th cousins. The plot below provides a visual representation of the interquartile range and the outliers based on genetic distance (GD) and the time to the most recent common ancestor (TMRCA).
ANALYSISLargely due to two outlying relationships because of convergence and three very close relationships in the Cobourg line, those sharing a GD=0 have the greatest standard deviation (SD) of 5.15 generations. GD=1 and GD=3 are not far behind with standard deviations of 4.68 and 4.88 generations respectively. The relationships that are represented by these three genetic distances (0, 1, & 3) are more heterogeneous. This heterogeneity indicates that relationships at these levels are likely to be more different than similar.
Contrariwise, those with a greater genetic distance have a lower SD and are more likely to be similar in relationship. With a genetic distance of four through nine, the SD ranges from .98 to 2.71 generations. The most homogenous group is GD=8 with the lowest SD of 0.98 generations. Therefore, it appears that the greater genetic distance, relationships become slightly more predictable – at least within our surname.
CONCLUSIONWhile 111 markers aided in fine tuning our connectivity to those sharing our genetic and genealogical roots, genetic distance was not an accurate predictor of most relationships. Outliers can and do happen, as experienced with a GD=0; however, 78% of the participants at a GD=0 fell within the predicted level of six generations or less with a p ≤ .01, Two did not, and as explained earlier, this was due to convergence. We have seen close relatives (5th cousins and closer) having genetic distances up to 5, while 13th cousins, once removed have a GD=0.
The caveat is that this is one family of meager size from one haplogroup I-M253 (fine tuned with SNP testing to I-A10207). It may not be representative of everyone’s experiences; however, this information can be used as a reminder to exercise caution in using genetic distance as an indication that someone is more closely or more distantly related than he actually is. A prediction based on genetic distance alone might just be wrong.
EPILOGUEIt may be suggested by some that SNP testing is a more accurate predictor; however, we have not experienced this with our four participants thus far. We have seen genealogically closer participants not sharing the same SNPs as those who are more distant. We have tested two Sherburn family members (one from the Cobourg line), one Ganton, and one Thornholme.
The Ganton participant and one of the Sherburn family members share two extra SNPs (at acceptable quality) that are not shared by the other Sherburn member and the Thornholme participant; all other acceptable SNPs are shared by all four. The two Sherburn participants are eighth cousins. We need to continue to test others with the BigY; however, our results thus far are inconclusive in determining relationships or even identifying known family branches. Time will tell.