Trust the Tests?

Wouldn’t it be interesting to learn where you are from, ancestrally? And it’s easy now, right? Just buy a kit, spit into a vial, pop it in the mail, and . . . you’ll soon learn that 38.2% of your tribal roots lay in Mesopotamia, the land between the rivers, the cradle of civilization, for example. But just how accurate is that 38.2% number? How did they do that?

According to scientists, these testing and data analysis models are quite “young.” The human genome contains about three billion “letters” (biochemical markers that we convert to letters). The companies doing the testing focused on your global origins, like Ancestry.com and 23andMe.com, are using statistical analysis to locate sections of your genetic code that are similar to others in their database. Then, they match those with whom you share similarities to specified ethnic regions.

Another challenge that our genetics pose for these tests is “recombination.” Each egg and each sperm carry a different combination, or a different expression, of a parent’s genes. So, let’s say your mother is 50% French and 50% Native American. That makes you 25% of each, right? Not necessarily. Upon fertilization, sections of the different chromosomes may exchange information, and even combine and rewrite sections of DNA to create new, different alleles. Other sections of DNA strands may actually be broken, and other sections from the other genetic parent are synthesized, to create new sections of code, which differ from the genetic code of both parents. This explains why the test results for siblings, with the same parents, can be dramatically different.

Genetic testing for health concerns is also quite immature. Even there, different testing companies interpret the sequences, and their importance and prevalence among other individuals, differently. And of course, testing for health disorders, now or their future likelihood, carries with it many ethical questions, and even insurance concerns.

So, should everyone get their double helix tested and compared to the databases? If you are considering genetic testing for health reasons, you should consult with your physician. If you are curious about your biological connections to broad geographic regions of the planet, and recognize that the results are a statistical analysis, then by all means . . . test away!