The other day the subject arose in a Facebook group about
the possibility of matching someone at 67 Y-STR resolution while simultaneously
not matching that same person at 37 markers. The conclusion was that this was a
rare occurrence.
In our project, several
participants were not matching documented relatives with the same surname at 37
markers, but they had subsequently matched these same individuals at 67 markers; I realized
that this was a significant occurrence in, at least, our project and set out to
see if it included non-family members as well.
SURNAME PROJECT BACKGROUND
Since the 1970s, three researchers have been cataloging past
and present descendants of two extant and three extinct families with our
surname that ramified in what is now the Ryedale District of the present county of
North Yorkshire, England. It is estimated
by counting the number of cataloged males that 296 exist to the present. With a 5% margin of error, that number increases
to 311. We are a very low frequency
surname that has three current variations Owston (72%), Ouston (26%), and
Owston-Doyle (2%).
The Owston/Ouston DNA project began in 2010 and has risen to
33 Y-DNA participants. About 10.6% of
the entire male population of our surname has had their Y-DNA tested. Not counted
in this percentage are six other Owston males who have tested autosomally and
most certainly match the surname haplotype due to matching autosomal DNA to those
who have tested their Y-DNA. Four of these
males have been identified as having the I1 (I-M253) haplogroup via
23andMe. Our participants were recruited
from the United States, England, Canada, New Zealand, Australia, and
Finland. Including all autosomal
participants, we have 62 members total.
Of our 33 Y-STR participants, ten have a paper ancestry to
one of the two extant families, but these ten have ancestral non-paternal events and do
not match the family modal haplotype. Five
of the remaining 23 tested at GeneTree with a 43-marker test between 2010-2012. The remaining 18 have all tested at Family
Tree DNA at 111 markers. In addition, 15 have tested with the Big Y (with two
tests pending).
Of the 18 participants, there are 153 relationships that range
from a sibling pair to 13th cousins, twice removed. Relationships of
12th cousin and beyond are estimated due to onomastic evidence
linking the two families to a common source born in the latter half of the 15th
century; the closest possible relationship is used for the estimates; the relationships
should be no further than two additional generations than our estimation.
The first documented use of the surname in the region dates
to 1452. Big Y participants from both
families share A10206 and 14 additional phylogenetic SNPs. The Sherburn family
(including its Cobourg and Ganton subsets) all share BY31751, while the
Thornholme family members share the A15739 SNP.
67-MARKER MATCHES ABSENT AT 37 MARKERS
In analyzing the matches of 18 matching FTDNA Y-STR participants
in the Owston/Ouston DNA study, 100% of the men who tested at 67 markers
matched at least one individual who was not found in their 37-marker match
list. The numbers ranged from one to six non-matching individuals at 37 markers
with the average being 3.77. The percentage of non-matches at 37 within
the 67-marker match list ranged from 3.6% to 35.3% of their total 67-marker matches. An average of 14.1% of their 67-marker matches
were absent from their 37-marker match list.
The following table shows the total matches at 67 markers and the number of these matches that are missing from their 37-marker list. A percentage of the whole is also provided.
KNOWN FAMILY 67-MARKER MATCHES ABSENT AT 37 MARKERS
Eight of our 18 participants (44.4%) had non-matches with a
family member at 37 markers. This is a significant
number and can be greatly attributed to a person’s genetic distance from the family
modal haplotype. Even a genetic distance of 1 when paired with a genetic
distance of 4 will produce an absence of a match at 37 markers. This is a factor that could be extremely
important to genetic genealogists, as there may be a matching family member at
67 markers that does not show in the participant’s list at 37.
The following table provides an analysis of missing family members at 37 markers. In order to understand this phenomenon, the participant’s genetic distance from the surname model haplotype is listed. Each person should have 17 matching family members at 37 markers; however, eight individuals are missing one or several matches to family members they match at 67 markers.
The absent family members at 37 markers in our project included
the following relationships:
- One seventh cousin, once removed pair;
- One seventh cousin, twice removed pair;
- Two eighth cousin, once removed pairs;
- One eighth cousin, twice removed pair;
- Two ninth cousin pairs;
- One ninth cousin, once removed pair;
- One ninth cousin, thrice removed pair; and
- Three tenth cousin, twice removed pairs.
The 12 relational pairs represent 7.8% of the total number
of matching family relationships (153) at 67 markers.
An interesting development with absent matches at 37 markers
is that this phenomenon occurred intra-family within the Sherburn family and was
not present with matches to the more distantly related Thornholme family. Some of this may be attributed to a lack of viable
participants within the Thornholme family.
Although the Thornholme family is rather small with only 25
living males, all four lines have been tested. Of the 25 aforementioned males, 14 have
non-paternity events within their ancestries.
Of the 11 potentially remaining matching members, three have tested (one
at 43 markers). The other eight are
closely related to at least one participant who has already tested. Among those
not tested, the most distant relationship is that of a first cousin, twice
removed. It is not likely that any new
data would be gained in further testing any of the remaining eight Thornholme
men.
CONCLUSION
Do not discount the possibility that match may exist at 67
markers but be absent at 37 markers. In
our family, 100% of our participants were missing at least one 67-marker match
at 37 markers. Forty-four percent of our participants were missing at least one
family member at 37 markers. One participant
was missing six and another missing five family members.
While the data presented has a small sample size and is only
indicative of our singular family project, the results may differ from the
general population of FTDNA Y67 results. Therefore, it is suggested that a similar
analysis be replicated within a haplogroup project to see if the results are consistent.
