It probably doesn’t surprise anyone, but the learning curve for laboratory research is incredibly steep. Yesterday, it took me two hours to prepare 25 squirrel liver samples for the afternoon Genetics lab. We ran in to a multitude of problems, made mistakes, and made educated guesses as to how to remedy them. It was fun, but I wasn’t sure I was going to actually isolate any DNA by the end of the day.

Luckily, I did, but the samples were not adequately pure. We use a machine called the Nanodrop to analyze the DNA content and purity of our isolated samples. The Nanodrop is basically a tiny spectrophotometer. And a spectrophotometer is a machine that shoots light through your sample and measures the resulting wavelength, thereby determining the concentration or the makeup of your sample. Before this, I had only ever used a spectrophotometer in my Chemistry classes.

The Nanodrop is new to me, and for a nerd it’s kind of like a new fun toy. One of the parameters it measures is the 260/280 ratio, which is the ratio of absorptions at 260 nm and 280 nm, respectively. This measurement indicates the purity of the sample. The ideal 260/280 ratio is 1.8 for DNA. Different molecules have different absorption, so any variation from the ideal 1.8 ratio indicates contamination, usually by proteins.

My best sample yesterday had a 260/280 ratio of 1.87, which is pretty good. For the purposes of our research it is an acceptable ratio, however some journals would require it to have a higher level of purity. I hope as I get better at the isolation technique my samples become more pure. This is especially important for when I move from squirrel livers to squirrel hair, because DNA is much more difficult to isolate from squirrel hair.

Which brings me back to the learning curve. Today, I actually felt like I knew what I was doing. I still don’t know much, but I know a little more than I did previously. This morning it took me 30 minutes to prepare 10 samples. One of the trickiest parts is actually pipetting the buffer into the sample tubes. Because the measurements are so precise, even a small bubble can have large consequences. And there are a lot of bubbles in the buffer. If I looked at my pipette tube and found bubbles, I would have to start over again. It is incredibly frustrating to spend 5 minutes attempting to pipette 180 microliters of solution into a tiny tube. But I’m sure I will get PLENTY of chances to perfect my technique.