Benjaman's Powell and Davidson Matches

In February 2009, Jim Barrett, Group Administrator of the Powell Surname DNA Project, contacted me regarding 34/37 marker matches Benjaman Kyle had with members of the study.  For about a year, I researched how these Powells might be related to Benjaman.
In the Spring of 2010, however, while I was reviewing Benjaman’s matches in the Sorenson Molecular Genealogy Foundation Y-database, I noticed a 27/28 marker match with a Davidson that I had not taken too seriously.  This match did not appear to be competitive with the matches with the Powells. But on closer examination I discovered the Davison match was just as important because of the way Sorenson scores its markers.  Whereas DNA Heritage and Family Tree DNA score each component of a multicopy marker separately, Sorenson counts them as a single marker.  This normalized the Sorenson match to 33/34, with a single mismatch on DYS458, one of the fastest moving markers on the test panel.  The Davidson Y-DNA results were very different from other Davidsons who had been tested.
The Sorenson site does not give you information on living family members, but the pedigree of the Davidson who matched Benjaman indicated that he was a descendant of Thomas Davidson who came to the US with a group of other Scottish LDS converts in 1852.   Very few members of the family moved away from Utah.  One of the exceptions was John McNeil Davidson, who moved to Wyoming in about 1905, then to Idaho, and finally settling at least between 1912-1915 in Central Point, OR.
When I compared the Davidson history with the history of the Powells, I found that both families were in Western Oregon in about 1915.  The map shows the locations of the two families around this time.  They were not that distant from each other along what is now I-5.  Further comparison of the families indicated that the Powells are descended from three Powell brothers who were preachers along the Oregon trail in the 1850s, about the same time the Davidsons were making their way west to Utah.  The story of John, Alfred, and Noah Powell can be read here.

There were many opportunities for the Davidsons and the Powells to be in the same area, so that it is possible that there was a nonpaternity event where a genetic Powell carried the Davidson family name.  A nonpaternity event can be an illegitimacy, an adoption, or a name change.  So far, we have not been able to determine when such an event occurred, but it is the most logical explanation why Benjaman matches a Davidson who is closer to Powells than he is to people with the Davidson name.
To illustrate the relationship, see the cladogram on the right.  Yellow circles represent a Y-DNA haplotype (profile).  The larger the circle the most people with that haplotype.  The lengths of the lines joining the yellow circles are proportional to the number of mismatches between those haplotypes, and the red lables are the markers these mismatches occur on.

The cladogram has been constructed on the bases of 32 markers because this is the number of markers the Sorenson database overlaps with that of FTDNA.