Peter Aldhous has a great piece of detective work in New Scientist, which has revealed a bizarre and sporadic glitch in the online software provided by personal genomics company deCODEme to allow customers to view their genetic data.
The glitch appears to be restricted to the display of data from the mitochondrial genome (a piece of DNA with a special fascination for genetic genealogists, since it is inherited almost exclusively along the maternal line). On several separate occasions the deCODEme browser presented Aldhous with a mitochondrial profile that was spectacularly wrong, differing from the profile in his raw data at 44 out of 93 positions.
It looks like the software glitch may have been fixed but it required some very astute observations by a knowledgeable user. And this case was pretty obvious with so many errors present.
What would happen with errors that are more subtle? Particularly when the data may be used to make medical decisions? I figure that these things will be worked out eventually but in the meantime, there will be a very strong need to carefully vet the results from applications such as this.