I normally don't get involved in this type of discussion, but I felt that a couple of points should be made so others could make the best use of these DNA tests.This type of DNA test is very useful in determining beyond reasonable doubt that two lines have a common ancestor.They do this by checking for the existance of a paternal gene that is only passed from a male parent to all male children.There is also a maternal gene that is passed from a female parent to female children.From what I have read, this test being conducted on male Welborn/Wilburn/Wilbourn/etc. is being done to check on the male gene presence.If it is found, then you can be assured that there is a common ancestor in these lines.
But if none is found either of the following possibilities exist:
1. There is no common ancestor in the lines being compared. 2. There was an adoption of a male child in the line of the individual being tested.These adoptions don't always show up in the records. 3. There was one or more Welborn wives in this individual's line who were unfaitful and produced a child by another man.These events would rarely show up in records.A brother of such a child could probably pass the gene along, so the lack of the gene in an individual would not preclude the two or more compared lines from having a common ancestor.
There are usually 7 to 10 generations back to the common ancestor, and the odds are large that one of the decendants could have had these types of events.Most of us don't like to believe that this could happen in our families, but it is very common especially in the early years of this country when men were away.This Welborn gene could also show up in another line with a totally different name if the man was the unfaitful party.
The bottom line is that these tests can show a common ancestor in multiple lines but can't show that there is no common ancestor in two or more lines with the same or varied spellings of the same name.
I would hope that anyone conducting these tests would share the results, if two lines were shown to be connected.After all, the purpose of these test would be to further the knowledge of the makeup of the family lines.