Why don't we already have a Gila genome?

When talking about this project, many people have expressed surprise that we don't already have the genome of the Gila monster. In fact, we have genome sequences for very few species! Why is the perception so much different from reality when it comes to genomes?

Without having done a formal study, but I think part of the reason for the surprise is that with the rise of personalized genomics testing (like 23andme and ancestry.com), it seems like all it takes to get your genome sequenced is spitting in a tube and paying a couple hundred dollars. But, there are several misconceptions that arise from the popularity of personalized genomics testing.

Paying for a genome. The first misconception is that generating a genome is cheap. It isn't nearly as expensive as it once was, but just the actual sequencing of a whole genome that we are very confident in can take several thousands of dollars. So why is personalized genomics testing on the order of hundreds of dollars, but we're claiming it is going to cost upwards of $25,000 for a Gila monster genome? Part it has to do with how much of the genome we are going to sequence.

Part of a genome. Personalized genomics testing does not look at every position in your genome? Instead it takes a small snapshot (several orders of magnitude smaller than your whole genome) of the regions that are typically variable between people. With this project, we are going to be generating the DNA sequence for between 100-1,000 times MORE sites than are analyzed with commercial personalized genomics testing. That's a lot more DNA to analyze!

Building a puzzle. Personalized genomics testing can also return your results in weeks, but it is going to take us many months to assemble the Gila monster genome. This is because another challenge of doing the kind of genome sequencing we want to do is that we don't have a close reference. So, imagine each genome sequence is a puzzle. Putting a human genome together is like getting the puzzle (there's usually a few pieces duplicated and a few pieces missing), and having an idea of what the shape of the puzzle is, and what the picture is supposed to look like. Putting the Gila monster genome together is like getting a puzzle (again with some duplications, and some missing pieces), but not knowing the shape, or what the final picture is supposed to look like. Because of this we need to sequence much more (so we can find overlapping pieces of the puzzle), and use a lot more computer-time, to analyze the possible combinations of putting the puzzle together.

Moving forward. One of the fantastic parts of this project is that once we are done, we will have a high quality reference sequence for the Gila monster that will make analyzing the genomes of other Gila monsters much easier and cheaper, and will also provide a closer reference genome sequence for many species. The genome we generate with this project will be made publicly available and anyone will be able to use it for their research (or just for fun!).