DNA Testing

by Gregory J Winters
April 2008


One of the most significant developments in the world of genealogy since the advent of the personal computer is the breakthrough in the quality and easy availability of DNA testing.  For a mere few hundred dollars, a person can purchase a genetic profile which can be added to databases and matched with others, possibly connecting with others who have done the same - in short, discovering family members that they didn't even know existed!

As is the case with all new technologies, however, expectations tend to run high while actual results run short.  If you are considering having a DNA test performed, you might want to read the following so that you are more aware of what the results will actually mean.

First, it might seem surprising, but there are over two dozen companies which now offer consumer-level DNA testing and at a variety of prices ($100 to $900), so be sure to shop around.  Close to a half-million people have already taken the plunge, and some of the results have already made headlines, most notoriously the link between the descendants of slave Sally Hemming with her owner, Thomas Jefferson.

Sociologists have already been looking into the wider ramifications of the public's conclusions regarding DNA testing.  Already there are cases of individuals who are attempting to use the results of the tests to identify living biological relatives who might otherwise not wish to be known, as in the case of adoptions or criminal cases.  The genetic breaking down of the 'black-white' barrier has become an agenda for some, spurred by recent events as the genetic linking of Barack Obama and Dick Cheney.

Already, however, there are cases being logged of problems associated with over-reactions to test discoveries.  Reports are surfacing of people who have experienced undue emotional distress, others have changed the way they are reporting their ethnicity on job applications and medical questionnaires.  There is even a concern that some people might attempt to claim government benefits and other considerations because of a revealed link to a particular 'minority' group.

Without going into the scientific mumbo-jumbo, we'll just say that there are basically two types of DNA tests - the mitochondrial DNA test, which examines the maternally inherited genome, and the Y-chromosome test, which looks for 'short tandem repeats' in the paternally inherited chromosome.  (There is a newer, third type of test which examines 'autosomal' markers in a much greater number in an attempt to improve accuracy and increase the number of candidates in the pool.)

If direct matches can be made amongst those who have been tested, then the results are generally accurate.  Problems arise, however, if the results are 'stretched' in the attempt to trace era or geography.  In these cases, there usually isn't enough hard information from the standard tests to make conclusions, but some of the testing companies are known to 'suggest' possibilities which are many times assumed as fact by customers.

Another characteristic of the 'recreational' DNA testing companies is the tendency to play upon the general public's coarse understanding of human biology and frame results within their customers' expectations.  For example, scientists know that there is little actual evidence for the traditional 'four fundamental human races' (African, European, East Asian, and Native American) assumption, but the public continues to cling to this notion, so often, DNA results are used to associate the customer with one or more of these groups.  This is a wholly arbitrary assumption since there are numerous exceptions to the 'rule' of race, e.g., dark-skinned East Asians being classified as 'Africans' primarily because of their overall appearance.

Interestingly, many of the testing companies seem to be aware of some of the complexities.  Browsing their websites, one finds more straightforward information in their FAQ pages, but somehow, this information is watered down or even missing from the promotion pages.  Legal scholars are wondering if public concerns such as the well-documented data regarding genetics and disease will carry over into privacy problems with the DNA testing.

To be fair, most of the testing companies have responded to the concerns raised by scientists and sociologists and have taken steps to improve their offerings, particularly when it comes to the expectations of their customers.  An objection raised by the testing companies is that they cannot be held responsible for customers misusing or misunderstanding their products, as could be said of many other enterprises in our society which have been 'accepted' for years.

I would recommend that if you are considering a DNA test, take the results for exactly what they are and don't attempt to make anything else out of them.  The idea is to see if there are others out there who share your genetic background, but only if they wish to make this information available to you.  If anyone wishes to share their results or discoveries with this website, the offering will be more than welcome!

Information for this article was derived in part from the following resources:

Bolnick, Deborah A., et al.  "The Science and Business of Genetic Ancestry Testing."  Science 19 October 2007:  399-400.

Frudakis, Tony.  "The Legitimacy of Genetic Ancestry Tests."  Science 22 February 2008:  1039.