Genetic genealogy has the potential to reveal information about your health (for example, DYS464 can reveal infertility and sequencing of the entire mtDNA genome can reveal mutations that are suspected of being associated with certain disorders). Although I usually don’t consider this possibility to be serious enough to discourage genetic genealogy testing, I do believe that people should be aware of the possibility before being tested.
A new study in the American Journal of Human Genetics (available here) examined the frequency of ten (potentially) pathogenic mitochondrial point mutations in 3168 neonatal cord blood samples. Of these samples, a total of 15 (or 1 in 200) harbored one or more of the mutations.
Interestingly, the mtDNA of 12 of the 15 samples were heteroplasmic, meaning that their cells harbored both mutated and non-mutated mtDNA genomes. Figure 1 from the paper, above, shows the percentage of mutated mtDNA in each of the 15 samples with mutations, from nearly 0% to the 100% in the three homoplasmic samples. ... Click to read more!