When I randomly discovered 23andMe I was instantly fascinated by their silicon valley approach to just take genetics to a very pragmatic and mainstream level. The idea of concentrating on what seems to be important, but having thousands of people genotyped because the price is affordable seems to be a great idea to get a data basis that can lead to results not possible with far more expensive “traditional” studies. 23andMe offers genotyping for $99, but does not guarantee 100% accuracy (which does matter for the individual but probably not for large scale studies) and genotypes “only” about 10% of the genome (my estimation, I just compared the number of SNPs on each chromosome to the number of SNPs my 23andMe profile has data on; SNPs are estimated to contain about 90% of our genetic information).

So definitely a good deal of motivation to try it out was scientific interest, but I was also curious about what my own genetic code might show or not. When the data was ready I instantly spent about 2 hours reading through the results. At first the good news was almost all quick indicators were positive (no inherited diseases an no significantly elevated risks), but in the details there were a few surprises. For example the overview shows I am genetically lactose intolerant. Although it says “might still be tolerant due to environmental reasons” it is a surprise, because it is just definitely not the case. The genotype however is plausible considering inheritance (you can guess I was not the only person genotyped).

The cool thing about all reports about the risk of getting certain diseases or having certain traits is that it refers to the original studies it relies on and does not just give you a plain result, but instead list all SNPs (and the corresponding genes) that are relevant and the genotype you have. Sometimes it is just one SNP that has a fundamental impact, for example whether you have curly hair seems to depend on a single SNP. There even is a website calles SNPedia that aims to collect all information that is available about single SNPs.

Another interesting aspect of 23andMe is that they allow you to browse through your whole genome (at least the parts they genotyped), so that you can check your variants of SNPs, that are not yet used for the reports 23andMe provides. They also allow you to download the complete raw data in a human and machine readable text format (about 30 MiB)

All in all I am very happy I did try it, I learned a lot about genetics (for example how little effect genetics can have compared to the environment) helped science (at least I hope so) and also had fun in the process. By the way I have 2.7% Neanderthal ancestry.
(And yes, I know that from a data security / privacy perspective it might not be a good idea to send a DNA sample to California and have a small company there analyze it. While I do think there are some risks involved and would not want my heath insurance company to have free access to my genetics, I still think it’s worth the risk. As long as everybody is free to decide, I see no general problem. Read this interesting article.)