> "We are supposed to believe that the technology can tell us accurately if a person has 1 copy of a variant, but it cannot determine if there are 2 copies? What does 23andMe report if there are 2 variants? Nothing?"
Actually, this sounds eminently plausible. As I understand it, a DNA microarray consists of a bunch of probes that each transmit a signal when they bind to a specific strand of digested DNA. A probe is either bound or not, and since you're applying a mixture obtained from multiple cells, there's many copies of each DNA sequence present in either case. There's no way you could establish whether or not two copies of the same gene were present in an individual cell.
I could be wrong (I'm a bioinformatician, not a biologist), and 23andme could be doing something interesting which reveals this data- in either case, I'd be interested to hear. But this makes fairly bad advertising copy- everyone else with the same cursory understanding of this technology is going to have the same thought, and think that you don't even have said cursory understanding if you don't explain your reasoning better [1].
[1] For that matter, you come off as wildly unscientific simply because you make this sort of conjecture without citing sources. There is a resource out there, somewhere, that would confirm or deny what you're saying, and your ability to make a credible scientific statement rests on you finding it.
Actually, this sounds eminently plausible. As I understand it, a DNA microarray consists of a bunch of probes that each transmit a signal when they bind to a specific strand of digested DNA. A probe is either bound or not, and since you're applying a mixture obtained from multiple cells, there's many copies of each DNA sequence present in either case. There's no way you could establish whether or not two copies of the same gene were present in an individual cell.
I could be wrong (I'm a bioinformatician, not a biologist), and 23andme could be doing something interesting which reveals this data- in either case, I'd be interested to hear. But this makes fairly bad advertising copy- everyone else with the same cursory understanding of this technology is going to have the same thought, and think that you don't even have said cursory understanding if you don't explain your reasoning better [1].
[1] For that matter, you come off as wildly unscientific simply because you make this sort of conjecture without citing sources. There is a resource out there, somewhere, that would confirm or deny what you're saying, and your ability to make a credible scientific statement rests on you finding it.