Monday, October 13, 2008

DNA testing -- a perspective

I had my DNA tested recently by . They do 600,000 or so DNA SNPs for $399. I believe the service is invaluable. To my surprise, not only have I heard opinion otherwise, but also, almost everyone I've talked to would not do it themselves. With a view toward correcting misinformation about these kinds of tests, here goes a bit of info.

According to Chrissy, her mom heard on "Twenty Twenty" that these tests are unreliable and a fraud. This is utterly untrue. What is true is that there are some paternalistic "consumer advocates" out there who assume that all clients of these tests are stupid and would be ill served by knowing their DNA background. Some of them are physicians. I reject this opinion completely.

Cross comparison's between 23andme and decodeme for the same individual have shown that they are almost in complete agreement in their SNP calls for almost all 600,000 SNPs. Only a handful differed between the two testing companies. That disposes of the data reliability issue.

The allegations of unreliability probably derive from the well known fact that these are early days in the scientific INTERPRETATION of those results. 23andme provides interpretation for only 91 SNPs of the 600K. Furthermore, individual SNPs only are interpreted, when not only environmental influences must be taken into account, but also the DNA context of the OTHER SNPs must be taken into account. No company provides that contextual interpretation because few scientific papers are yet available.

Nonetheless, what is available already is invaluable. One can determine whether they carry the cystic fibrosis gene or many other highly deleterious (and beneficial genes). That is often a good enough indication for medical surveillance in a particular area (all depending on the individual results). Sergey Brin, founder of google and husband of the lady who founded 23andme now knows that he carries the Parkinson's gene and since his mother already has Parkinson's he is now motivated to fund research in that area and also undertake medical surveillance of his own condition.

I now know I am at risk of thromboembolism and maybe a few other things at lower risk. I am actually relieved to know I have so few risk factors. Almost all humans have some risk factors. I was able to run my DNA file through the Promethease program by an another company which turned up a few more things that 23andme choose not to display because they do not yet regard them as sufficiently proven. That is fine by me. The Promethease program warned me of a possible Warfarin sensitivity. If I should ever have a heart attack or stroke, I'll simply warn the doctor to use a reduced dose or an alternative medication. No problem. In short, I find the service invaluable from a medical perspective.

As chance would have it, the 23andme forum also turned up a request for people with a certain profile. It turned out I fit that profile on my Y chromosome and it now appears I am among the first seven people to be discovered for a new previously unknown R1b1 clade of the Y chromosome. Very interesting. The experts seem to think this will greatly change scientific interpretation of the Celtic history.


Lynnis said...

I think it's good because it puts to rest the speculation about a lot of the genetic problems you thought you had. Now you know that your actions are responsible for the condition of your health. Any more research into little known genes will probably just cause you to worry.

Gordon said...

Maybe this is why I always thought Ed was rather strange and different.

Maybe this is why my children think I am strange and different. The new Y chromosome clade is apparently a relatively small and ancient group within the overall European clade.