Monday, June 04, 2012

[Health and Fitness, Science] In My Genes

In My Genes: I had my DNA genotyped. What that means is I paid a company to look for markers in my DNA that are known to relate to certain traits. Here's how it works: You hit a site called, send them money and they send you a little vial into which you spit. You enclose the vial into the supplied shipping material and then a couple of weeks later, you DNA has been read. Somewhat more robust than the gypsy palm reader over the pawn shop. You get extensive, and password protected, results online.

And really there is an astounding list of the results. Everything from disease susceptibility, carrier likelihood, miscellaneous traits, ancestry -- just a ton of interesting things you can learn about yourself.

Of course, you have to be careful about interpretation or you could be misled. Let's say the results suggest you have an elevated propensity to contracting Disease X. First you need to understand what that means. It means that when scientists looked at a certain population, people with specific genetic attributes showed a higher propensity for attracting Disease X. Note that it does not mean you have the genes that cause the disease. It is just a correlation that was observed, that's all. It could be like the relationship between eating ice cream and crime. (Old saw: There is a correlation between the amount of ice cream sold and crime. An unsophisticated person might conclude that eating ice cream is a cause of crime, but in fact it is heat that causes both crime and ice cream sales to rise.)

Also, you need to understand how confident we are in the correlation is. 23andme does a good job of this, using a star system. For example, four stars may mean multiple independent experiments have verified the correlation, two stars might mean that it was seen in one experiment but another was inconclusive, etc.

Then you need to understand the severity of the results. For example it could be that Disease X typically appears in .1% of the population, but in people with your profile it shows up in .2%. That's a 100% increase, but still a very trivial probability of attracting it.

Lastly, you have to understand that most things have both a genetic and environmental component. Personal example: my results indicate an elevated susceptibility to lung cancer. This is fascinating since there has never been any in my family that I am aware of, but the fact of the matter is that lung cancer risk for people who have never smoked is small so even though I have an elevated risk from a strictly genetic standpoint, from a holistic standpoint I'm still unlikely to get struck. In this case environment trumps genetics. (Note: Scientifically speaking, I may have just jinxed myself.)

Judging from the discussion boards at the site, the understanding of probability and correlation by the broader public is a well nigh non-existent. Tiny increases in probability are seen as definitive reasons for events that are more likely happenstance. Even a minor, unsubstantiated increase in risk is given as the source of a relative getting afflicted. I am convinced that instead of geometry and trigonometry, after you have your multiplication tables down, math education should focus on probabilities and statistics.

Anyway, although I found my results fascinating, I didn't see anything that will alter my life at all. It is possible that something along those lines could turn up, and more importantly if I were a parent or starting a family I would absolutely get tests done on myself and my spouse and children, just in case something turned up. Yes, it's a long shot, but it would be worth the comfort factor.

They also can, at your option, keep your results on file and use it to match up against any new or updated research going forward. I have no idea whether anything useful will come of it for me personally, but given that I have gene markers indicating a propensity for longevity, I'm pretty sure I'll find out.