In my opinion, one of the things that really makes working in the Perry lab special is our ancient DNA lab (AKA aLab). Our aLab is a dedicated clean space where we can extract and process DNA samples from really old and/or degraded specimens. Members of the lab group have worked with bones and teeth from extinct species, as well as those from prehistoric specimens of extant (still living) species. Some examples include subfossil giant lemurs, gourds and squashes, and even taxidermied skin samples from Nittany lions, PSU's beloved mascot! |
Now you may have noticed my emphasis on the word clean in that last paragraph. If a sample is designated aLab worthy, it's likely because there's a very good chance that there's not much DNA left in the sample to begin with. This means that our top priority is preventing contamination. If we're going to the trouble of getting our target DNA out of a partially fossilized bone, we don't want any other DNA floating around in the sample decreasing our data integrity and taking up valuable sequencing space.
There are several things we do to keep our clean lab sterile. First and foremost, our aLab is in an entirely different building than our modern DNA lab. High quality DNA from modern labs is a particularly bad form of contamination because the longer DNA could potentially swamp out the smaller fragmented bits of aDNA during our processing. Once DNA has been extracted from a sample, it is prepared for sequencing in a process called library preparation - the DNA extracts are repaired and converted into "sequenceable" libraries that are barcoded for future identification during our data processing. Library prep involves an amplification step where whatever DNA strands are in your extraction are copied hundreds of times over to increase our sequencing depth (if you have lots of copies of each of the strands, chances are you won't miss anything when you're putting it all the DNA data back together after sequencing). The gif below depicts this process, called the polymerase chain reaction.
We do this amplification step in our modern lab, which means that our building is full of floating, microscopic DNA bits. So is every other building that contains a genetics lab. Everything aLab-related happens in the basement of one of the Physics buildings on campus, which is rather lucky for me because then I get to go see Dan more frequently during the day :) |
So we avoid the floating bits of DNA by keeping everything aLab-related out of those buildings. We also have to avoid all of the DNA that's sloughing off our bodies throughout the day: hair, skin, saliva, tears, sweat, mucus, all of these are possible contaminants when it comes to DNA work. The concern isn't as high for modern samples - odds are the material is fresh or preserved, so the sample's DNA should totally overwhelm contamination during the extraction and processing. But ancient DNA requires some suiting up.
Our standard aLab attire protocol begins before you even leave your house. A shower and freshly laundered clothes help to avoid contamination from the start of your day. Once there, we glove up, then put on our clean suits. These suits are basically footy pajamas' evil cousin, but keep our DNA to ourselves which is really all we can ask of them. We wear face masks and a second pair of blue booties that can be changed more frequently than the more-expensive clean suits. A second pair of gloves over your first completes the look, as long as you check the little mirror by the door to make sure any stray hairs (including eyebrows) are safely tucked away in our hairbands. This entire suiting up process occurs on a sticky floor mat in the doorway that catches any dust or hairs while we change. |
Stephanie Marciniak, our post-doc aLab manager, is vastly improving our lives by making our work in there more comfortable. Step one: Crocs that never leave the lab, both for cleanliness and for personal appearances haha. Bye bye booties!
The absolute worst part of wearing the suit is that it does its job: contains all of your you. You are breathing in your own breath for hours at a time, which you might not think will be that bad, but you'd be wrong. And I never realized how much I touch my face and hair every day until I worked in our clean lab haha. That said, the absolute best part of wearing the suit is throwing it away when you've gotten a few good uses out of it. Richard Bankoff, a grad student in the Perry lab, let me post the following video of him demonstrating our clean lab ridding-of-the-suit tradition.
As you've probably gathered, working in our ancient DNA lab isn't the most comfortable experience at times. But think about what we are doing in there: we are extracting DNA from specimens that are thousands of years old! No, we are not making clones dinosaurs or mammoths, and I am sorry if that disappoints you a little bit. We are taking a glimpse into the biological past of species that might already be extinct or sometimes right on the verge of becoming so. If our work can help us understand how a species might have lived, interacted with its environment, or be conserved, then the clean suit is totally worth it. Cheers, and I'll see you next week!