Fauquier County Tapscotts and DNA Testing

Today I received an email from a descendant of Cordelia Tapscott asking if she could get involved in DNA testing to show a connection with the Tapscotts possibly through testing with a male relative (e.g., a cousin). I wrote the following (slightly modified):

Thanks a lot for the offer. Unfortunately it appears to be almost (but not quite) impossible to use DNA to show relation between descendants of Ezekiel Tapscott, whose son James E. Tapscott was involved (somehow or other) in founding the Fauquier County Tapscotts, and descendants of Cordelia. The problem is that no matter how the descendancy occurred, any connection between you and a Tapscott involves a line with both males and females. A male descendant (a male Tapscott cousin for example) has the same problem. At some point there is a male/female break in the line so that it is neither paternal nor maternal and neither mtDNA nor yDNA testing can be used.  For the Fauquier County Tapscotts, there will always be a break (if our genealogical research is correct).

The only possibility to show your connection with Tapscotts would be with autosomal DNA and the results will not be easy to interpret since there will be many false negatives (due to large relationship distances) and many false or at least unimportant positives. Nevertheless, matches from autosomal tests could show something. For example, you and I are probably connected and could match with autosomal testing (which I have already had done through Ancestry.com). If we did match, it would be strong evidence that you are descended from Tapscotts. If we do not match (which is likely due to the distant relationship) nothing is proven. You may, therefore, wish to have Ancestry.com testing (which is only autosomal) done, though it is a gamble.

The mtDNA test, which you have had done, can be used to follow your maternal line, but this will not get to the Tapscotts, though it might be possible to get back to Elizabeth Percifull, wife of James E. Tapscott. One possibility would be to find living descendants of Elizabeth's sisters through female lines. It is quite likely that such descendants exist, but tracing and finding them would be exceedingly difficult. But a positive match between you and them would be very, very exciting.

I wish I could be more optimistic about proving a Tapscott connection for the Fauquier County Tapscotts using DNA.