Sequencing Within Reach

As you can see from the graph, the cost of figuring out what someone’s DNA looks like is dropping like a stone. You can get your DNA sequenced for somewhere between 10 and 20 thousand dollars. When I started writing this blog back in 2007, it would cost you around 350 thousand dollars.

And it is even cheaper than this if you want to focus on just your genes. 23andMe is offering that very service for less than 1,000 dollars. Your DNA is finally within your grasp!

This drop in price is great news for scientists. They can now get more DNA sequenced for less money. This is driving genetics forward at breakneck speed.

This will probably also be great news for patients. For example, in the near future cancer patients will get the DNA in their tumors sequenced so they get prescribed the right medicine. We aren’t there yet, but if costs keep dropping, we will be soon.

For casual consumers, though, affordable DNA sequencing is much less useful. In fact, it might even make a difficult situation worse.

Right now we can get the results of a million or so of our bits of DNA. Some of these SNPs are within genes and some are outside of genes.

These SNPs have been looked at in lots of experiments. This means we have at least some idea about how each relates to various diseases. The same won’t be true of the new data that will be made available to you.

There are going to be changes in your genes that scientists haven’t seen before. And in many cases they won’t be able to tell you whether a certain change matters or not. You will end up with a bunch of differences for which there is little or no information. If you’re a worrier, this is going to cause problems.

Let’s take an easy example, cystic fibrosis (CF). Most of the time CF is caused by one or more of a defined set of DNA differences in the CFTR gene. Genetic testing now looks for changes known to cause CF.

Unfortunately, CFTR is a gene with a lot of changes, many of which have no effect. What this means is that many of us will have differences in our CFTR gene that haven’t been seen before. Will they cause cystic fibrosis? For many differences, we won’t know for sure.

This information may ultimately be helpful for scientists if they find enough people with particular differences. But it may not be that helpful to you. In fact, if you’re a worrier, you may be unnecessarily concerned about your kids ending up with CF because of your unique version of the CFTR gene.

And this is the easy example. Other diseases happen when many different gene versions all work together in a certain way. Some combinations of these gene versions will lead to disease or increased risk of disease and some won’t. If you pile on enough genes, you suddenly have so many combinations that it becomes very difficult to make any really predictions with only a few people’s DNA.

Right now I think it is safe to say that with genetics, we have lots of data but little understanding. To increase our understanding of human genetics, everyone should probably throw their DNA into the ring for scientists to study. The question is when do you want to know the results of what scientists are finding. At an early stage when everything is muddled or at a more defined, later stage.